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Cornell Mniversity Library
THE GIFT OF
A: %.G08\ 2sfio[as
A TEXT-BOOK
OF
ZOOGEOGRAPHY.
ZDondon: C. J. CLAY anp SONS,
CAMBRIDGE UNIVERSITY PRESS WAREHOUSE,
AVE MARIA LANE.
AND
H. K, LEWIS,
136, GOWER STREET, W.C.
aos aa
ci §
Glasgow: 263, ARGYLE STREET.
Deipsign: F. A. BROCKHAUS.,
Pew Work: MACMILLAN AND CO.
‘suotboy peotudeaboobooz furmous dey
oBpriqmeg uos[ly FT
Cambridge Patural Setence Manuals
BIOLOGICAL SERIES.
GeEvERAL Eprtor :—ArtuHur E. Saipiey, M.A.
FELLOW AND TUTOR OF: CHRIST'S COLLEGE, CAMBRIDGE.
A TEXT-BOOK
OF
-—ZOOGEOGRAPHY
BY
FRANK E. BEDDARD, M.A. (Oxon.), F.BS.
PROSECTOR OF THE ZOOLOGICAL SOCIETY OF LONDON, AND
LECTURER ON BIOLOGY AT GUY’S HOSPITAL.
CAMBRIDGE:
AT THE UNIVERSITY PRESS.
1895
4
[All Rights reserved.}
Cambringe:
PRINTED BY J. & C. F. CLAY,
AT THE UNIVERSITY PRESS.
PREFACE.
L this volume I have attempted to give the principal
facts and conclusions of Zoogeography, without an
undue profusion of detail. A few examples only have
been selected to illustrate the principles. As far as
possible I have endeavoured to use instances that have
not been made use of by Mr Wallace in his two works
upon this subject. I have taken Kerguelen Island and
Fernando Noronha as examples of oceanic islands; the
facts of distribution and the inferences to be drawn are
illustrated largely by the earthworms; and in other
places I have availed myself of some of the more recent
sources of information. Naturally a large portion of this
book, as must be the case with any book upon Geographical
Distribution, is based upon the two indispensable treatises
of Mr Wallace. I have also found great assistance in
Prof. Heilprin’s work upon Distribution in the Inter-
national Scientific Series, and in an excellent manual
vi PREFACE,
upon the same subject by M. Trouessart; I have checked
and added to the facts that I had accumulated by a careful
comparison of them with the article Geographical Dis-
tribution in Prof. Newton’s Dictionary of Birds. Numerous
special memoirs have also been laid under contribution,
a reference to which will be found in the proper place.
FRANK E. BEDDARD.
Lonpon. é
November, 1894.
CONTENTS.
CHAPTER I.
THE GENERAL FACTS OF THE DISTRIBUTION OF ANIMALS.
Introductory, p. 1. Locality and Station, 5. Cosmopolitan
groups, 8. Restricted groups, 10. The meaning of a restricted
distribution, 12. Discontinuous distribution, 15. Separate areas of
the species of a genus, 18. Distribution of Rhea, 19. Distribution
of Ibexes, 20. Distribution of the Cassowaries, 23. Classification
and Distribution, 25. Distribution of the Gallinaceous birds, 26.
Distribution of the Edentata, 31. Distribution of the Cuckoos, 35.
Distribution of Chelonia, 38. Distribution of Lizards, 40. Distribu-
tion of Crocodiles, 43. Distribution of Snakes, 46. Distribution of
Batrachia, 47. Distribution of Scorpions, 49. Distribution of Land
Planarians, 53. Distribution of Earthworms, 57.
CHAPTER I.
ZOOLOGICAL GEOGRAPHY,
Mr Sclater’s regions, 72. Mr Huxley's regions, 75. Other sug-
gested regions, 76. Mr Sclater’s regions the most convenient, 78.
The six Zoological regions of Mr Sclater, 88. The Palearctic
region, 88. The Nearctic region, 93. The Ethiopian region, 98.
The Oriental region, 102. The Neotropical region, 107. The
Australian region, 118. Some graphic methods of presenting the
facts of Distribution, 118.
CHAPTER III.
THE CAUSES WHICH INFLUENCE THE DISTRIBUTION
OF ANIMALS.
Distribution not dependent upon temperature, 124. Distribu-
tion of Crustacean Arcturus as illustrative of connection between
range and temperature, 125. The country inhabited by an animal
Vill CONTENTS,
is not necessarily the only one in which it can flourish, 128.
Similarities in the faunas of distant countries, 129. Problems of
Distribution and Evolution, 131. Means of Dispersal of Animals,
134. The influence of geological terrain upon faunas, 136. Dispersal
of Oligocheta, 138. Dispersal of Mollusca, 140. Dispersal of
Amphibia, 145. Dispersal of Reptiles, 147. Evidence of capacity
for Migration on the part of a given animal, 150. Influence of
human interference upon Migration, 151. The existing Distribution
of land and sea considered in relation to Zoological Geography, 155.
Evidence in favour of Permanence of Oceans, 156._ Evidence against
the view that existing Oceans have not largely changed their
areas, 159. Evidence in favour of a formerly more extensive
Antarctic Continent, 164. ‘“ Lemuria,” 176.
CHAPTER IV.
“THE FAUNA OF ISLANDS.
The Fauna of the British Isles, 183. The Fauna of Madagascar,
187. The Fauna of Fernando Noronha, 190. The Fauna of
Kerguelen, 193. The Fauna of the Galapagos, 195. The Fauna of
New Zealand, 199. Fauna of the Sandwich Islands, 203. General
observations upon the Fauna of Islands, 204. Continental Islands,
205. Oceanic Islands, 207. Anomalous islands, 210. Some pecu-
liarities of island animals, 212.
CHAPTER V.
SOME THEORETICAL CONSIDERATIONS.
The bearing of the facts of distribution upon the places of origin
of different groups, 220. The place of origin of the Marsupials, 222.
Theory of the Polar origin of Life, 227.
Map shewing Zoogeographical Regions 4 , Frontispiece
ay distribution of Edentata . 3 . to facep. 32
5 95 ay Earthworms . : » oy 65
Struthious Birds . ,, ,, 168
bid ” ”
Lemurs . 97 a. BF
” ” ”
CHAPTER I.
THE GENERAL FACTS OF THE DISTRIBUTION OF ANIMALS.
Introductory.
THE entire world both land and sea supports every-
where animal life. The extreme cold of the arctic regions
is not too intense to permit of the existence of at least a
few forms of life, while the warmer regions of the globe
have everywhere an abundant fauna, which increases
towards the tropics; it is even probable that the icebound
antarctic continent, if it could be explored, would be found
to possess some inhabitants. .
The most elementary knowledge of Zoology is sufficient
to enable us to see that, while terrestrial life is as
abundant as marine, the kinds of animals inhabiting these
diverse situations are different. We can distinguish in
fact between purely terrestrial and purely aquatic animals,
The latter group can be again divided into two great
classes, those which inhabit the sea and those which
inhabit the fresh waters of the land. There is however
no absolute break between these various groups. The
B, Z. 1
2 TERRESTRIAL AND AQUATIC ANIMALS. [cH. I
fresh waters themselves gradually pass into salt at the
mouths of rivers; while a marsh, particularly one that is
subject to periodical drying up, is to some extent inter-
mediate between the land and the water.
Corresponding to this absence of hard and fast lines in
inorganic nature we find a similar absence of definiteness
in the animals which frequent the waters, the dry land,
and the transitional areas. The duck tribe are equally at
home when swimming in a lake and when flying from one
pool to another. There are even ducks which perch on
trees. Closely allied Crustacea may be marine, estuarine,
fresh water or terrestrial in habit. Certain sharks, nor-
mally marine, ascend rivers for some distance, and the
Manatee of the west coast of Africa and the east coast of
America is quite as much at home when browsing upon
the marine algae of the coasts of those continents as when
living in their rivers. Though we may broadly separate
animals into terrestrial and aquatic, there is no large
group of animals which is exclusively terrestrial. Even
insects which approach nearest to this condition have
plenty of aquatic representatives; there is even a peculiar
genus of bugs, Halobates, which inhabits the open sea far
from land.
On the other hand, there are groups which are purely
aquatic, and even some which are only marine, beg never
found in fresh water; but these are few. Among Verte-
brates fishes are the only group which can be said to be
almost absolutely aquatic; and here too there are some
slight exceptions. The well-known Climbing Perch, Anabas
scandens, can with impunity leave the streams which it
CH. T] HABITATS OF ANIMALS. 3
inhabits; the mud fish of Africa and America has lungs
as well as gills, and can suffer with equanimity the drying
up of the rivers in which it lives. Eels are said to move
from one pool to another across the intervening grass.
The curious little fish Periophthalmus voluntarily leaves
the sea and hops along its margin on the look-out for the
Mollusc Onchidiwm upon which it largely feeds. Among
Invertebrates there are more purely aquatic groups; and
these are exclusively marine. No Ascidian, no starfish,
brittle star, sea urchin, or sea lily has as yet been met
with except in the sea. Sponges and Celenterates are
without exception aquatic and for the most part marine,
their delicate organisation not being able to withstand
continued dryness. But these are positively the only large
groups which are purely aquatic. Many others are prin-
cipally aquatic, such as the Flat worms, with terrestrial
allies in the land Planarians, the Crustacea, the Annelids
and some others.
Not only can we draw these broad distinctions between
the habitats of different animals, finding one to be terres-
trial, another aquatic and a third amphibious; we can also
assign to each a definite place upon the land or in the
waters. The Indian Ocean is frequented by creatures
which are unknown in the colder waters of the North Sea;
the Mississippi has alligators which the Thames, for ex-
ample, has not. It is a matter of common knowledge that
the tiger is restricted to Asia and the puma to South and
certain parts of North America; the elephant is unknown
beyond the old world, and it has even there a limited area
of range. It would be as surprising to meet with an
1—2
4 DISTRIBUTION OF LAND ANIMALS, [CH. I
elephant even in the most secluded of Brazilian forests as
to meet with a tiger genuinely at home in the neighbour-
hood of a peaceful English village.
That branch of Biology which is termed Geographical
Distribution, or, when applied to either animals or plants
only, Zoogeography and Phytogeography, is concerned
with facts such as the above; it has also to do with the
solution or attempted solution of the various problems to
which these facts give rise. The science is not limited to
a consideration of the animals which inhabit dry land.
But this volume will only deal with those forms, touching
incidentally upon some of the fresh water species, whose
distribution is apparently governed by the same laws as
those which govern the distribution of the purely terres-
trial animals,
We shall now commence our survey of the chief facts
in the distribution of land animals. It has been said that
every animal has its place in the world, which may be
wider or narrower. The country which is inhabited by a
given animal is called its area of distribution, its habitat
or locality. The converse follows that every tract of the
earth’s surface is inhabited each by its peculiar set of
animals. But they are not met with everywhere in that
area. Almost every year a new volume is published
giving a list of the birds of a particular county or it may
be district; anyone who will take the trouble to inspect
and compare a series of these volumes dealing with many
different counties will be struck by the fact that a given
species of bird may be absent from one list or stated to be
uncommon, while numerous records of its discovery will be
CH. I] LOCALITY AND STATION. 5
found in another. The same thing holds true of other
groups; the badger, for example, will be found in one wood
but will be absent from another; nevertheless generally
speaking this animal may be said to inhabit the greater
part of England, not to mention foreign regions in which
it is also found. Were we to put together all that has
been recorded of the range of this or any other animal
and colour a map of England in correspondence with those
facts, we should find that a large map would be coloured
by a series of closely set but separate patches of colour;
on the other hand a small map would practically have to
be coloured all over to indicate the range of the animal.
The reason for this is that the badger can only live in
certain kinds of country. It is not at home for instance
in bare chalky downs or on the tops of high mountains; it
prefers woods and the immediate neighbourhood of woods.
Locality and Station.
We must carefully distinguish between locality and
station. While the area inhabited by a species is usually
continuous, it by no means always happens that the station
consists of one continuous tract, Animals inhabiting
forests or moorland or pools are only found where the
suitable circumstances occur. But in such instances the
habitat of the animal may be wide, only broken up into a
series of stations. We should not regard a case of this
kind as one of discontinuous distribution. Often however
the local phenomena of distribution have not so clear an
interpretation. Every entomologist is aware of the often
6 RANGE OF LEPIDOPTERA. (cH. 1
capricious occurrence of butterflies and moths; we do not
now refer to marsh-loving or wood-loving species or to any
intelligible restriction of this kind. Out of a dozen fields,
to the eye equally well suited for the maintenance of a
given species of moth, in which for instance the food plant
is equally abundant, two or three or it may be only one
will be inhabited by the insect in question, which will
there perhaps swarm. Some years since a small moth was
found at Folkestone only in a particular tract of grass
with no obvious advantages—indeed the reverse, as it was
scanty and trodden under the feet of passers by—to the
exclusion of neighbouring grassy areas; this insect, known
as Tapinostola bondii, was abundant in this particular
locality but nowhere else in the neighbourhood. In every
local faunal list such and such a wood or field is given as
the locality for a particular insect, which would be equally
at home in other woods and fields, but is not as a matter
of fact found in them. To get the particular insect we
have perhaps to journey to another county or even to
another part of England; possibly a particular wood is
the only part of England where it is to be met with and
the next locality will be on the Continent. No doubt
some of these apparently capricious variations are to be
explained by advancing civilisation. Building, draining
and the gradual reclamation of the country are fatal to
insect life as a rule. But this will not explain every case
of capricious restriction to a few separated stations, such
as are so commonly met with among the Lepidoptera of
this country.
CH. I] WIDE RANGE OF CERTAIN FORMS. 7
The Range of Animals.
In the range of species we meet with every condition,
from world-wide distribution to the most restricted habitat.
It has been said that man is the only animal (with the
exception perhaps of his parasites) which is literally found
in every habitable part of the earth’s surface; but a few
others are almost as widely scattered. Among mammals
only certain bats are in this position, for though the
common mouse and the rat are found nearly everywhere,
it is very possible that man is responsible for this wide
dissemination. The Barn Owl (Strix flammea) occurs in
most parts both of the new and old worlds. It is true
that in different countries it has received different names ;
but the opinion of many is that these are at the most
local races which are hardly deserving of being separated
as species. The Painted Lady (Vanessa cardut) is an
example from another class of animals which has an
equally wide range. This butterfly extends from Europe
to the Islands of the Pacific and to New Zealand, but is
not found in the West Indies and certain parts of South
America. The common Red river Worm (Tubifex) seems
to be universally spread. At any rate examples from so
distant a spot as New Zealand do not differ in any
appreciable point from those of England. A species be-
longing to another family of Oligocheta, Henlea ventri-
culosa, occurs in Europe, in the territory of the Khirghese
Tartars, and in New Zealand.
The now extinct Large Copper Butterfly was formerly
found in abundance in the Cambridgeshire fens, but found
8 ANIMALS WITH RESTRICTED RANGE. [cH. I
nowhere else in the world. The limitation of particular
species of humming-birds to particular peaks of the Andes,
and of snails to particular valleys, are other examples.
Francolinus Kirki of the island of Zanzibar is almost as
striking an instance of the same phenomenon. The Ven-
dace (Coregonus vandesius) restricted to Loch Maben in
Dumfriesshire is an animal with a still more limited range,
and several other examples might be given, particularly
from the faunas of islands. The two extremes are natu-
rally connected by numerous intermediate stages, where an
animal has a more or less limited habitat.
Cosmopolitan groups.
There are comparatively\ few groups of terrestrial
animals which are truly cosmopolitan, As the groups
get smaller the number of those that are cosmopolitan
decreases. That is to say, there are more cosmopolitan
families than genera, and more genera that are cosmo-
politan than species.
Mr Wallace enumerates in his work upon Geographical .
Distribution no less than sixteen families of birds which
are really cosmopolites; they are, Corvide (Crows) and
Hirundinide (Swallows) among Passerines; Kingfishers
among Picarie; among other land birds, Columbide
(Doves), Tetraonde (Grouse), Falconide (Hawks), Stri-
gide (Owls); among waders Rallide (Rails), Scolopacidee
(Snipe), Charadrie (Plovers), Ardeidw (Herons); among
aquatic birds Anatide (Ducks and Geese), Larid@ (Gulls),
Procellaride (Petrels), Pelecanide (Pelicans) and Podici-
CH. I] COSMOPOLITAN GENERA. 9
pedide (Grebes). Only one family of mammals are really
cosmopolitan, namely, the Vespertilionidw. There are
several families of butterflies and moths which are in
this position and nearly all the families of beetles. The
Helicide alone of the terrestrial Mollusca are universally
distributed, and among earthworms the two families Lwm-
bricide and Cryptodrilide. It is a significant fact that of
these families by far the majority are winged creatures,
which are naturally less restricted by barriers. The earth-
worms form an apparent exception which is not really so;
for it is highly probable that the universal range of these
families is due to human agency. Again, it is important
to notice that of the cosmopolitan birds at least eight are
largely aquatic in habit or frequent the margins of streams
and lakes. The conditions of life for aquatic birds are
more similar in different parts of the globe than those
of purely land birds. Moreover all these families are
numerous in genera and species.
Cosmopolitan genera are fewer in proportion. Among
birds we have Hirundo (Swallow), Pandion (Osprey), Stria
{Barn Owl), Rallus, Porzana (Rails), Gallinula, Fulica
(Coots), Numenius (Stilt Plovers), Limosa (Godwits) and
several other Scolopacide, Charadrius (Plovers), Ardea
(Heron), Nycticorax (Night-heron), Anas (Duck), Sterco-
rarius (Skua), Larus (Gull), Sterna (Tern), Puffinus (Puffin),
Procellaria, Fulmarus (Petrels), Pelecanus (Pelican), Pha-
lacrocorax (Cormorant), Podicipes (Grebe). Among butter-
flies the genera Pyrameis (Painted Lady), Polyommatus
(Blues), Pieris (Whites), Papilio (Swallowtail), Pamphila
and Hesperia (Skippers) are universally distributed.
10 COSMOPOLITAN SPECIES. (cH. I
Macroglossa, Cherocampa (Hawkmoths), Macrosila (Clear
wing) among moths are also cosmopolitan.
As to species there are comparatively few that have a
world-wide range; the most striking example among birds
is the Osprey. Gallinula chloropus and Totanus incanus
have the same distribution. Among insects it is more
difficult to discount the interference of man, which may
be responsible for a world-wide distribution. Anosia
pleaippus is a butterfly which appears to be found almost
everywhere. I have dealt on another page’ with those
species of earthworms which are cosmopolitan or nearly
so and arrived at the conclusion that it is in those cases
really a question of transport by man. The same argu-
ment seems according to M. Trouessart to apply to the
cosmopolitan Gecko, Platydactylus facetanus. Even the
Lepidoptera above mentioned are not above suspicion
on this score; the pup could so easily be accidentally
conveyed to the most distant countries. The common
bee-fly (Eristalis tenax), which so closely resembles to
the superficial inspection a honey-bee, has reached as far
as New Zealand, doubtless by the same agency.
Restricted groups.
We have besides Universally distributed groups some
of which are remarkably limited in their range, Naturally
this applies most of all to species and least to families,
The majority of species have a more or less restricted
range, so much so that it would be impossible to give any
1 y, infra.
CH. 1] GENERA AND SPECIES OF LIMITED RANGE. 11
catalogue of them. A few of the more remarkable ex-
amples may however be referred to. The most striking of
these are certain fishes which are limited to a single lake;
thus the Lough Killin Charr is confined to the lake of
that name. A small moth, Ornia devoniella, was once only
found in Devonshire. The monkeys of the genus Brachy-
urus, comprising three species, are limited each to a
moderately small forest tract in South America. The
majority of examples of species with a limited range
are of course to be found upon oceanic islands. Not
only are there species with a very small range in space
but also genera. Here again the most numerous examples
are to be found on oceanic islands such as the now extinct
Starling, Fregilupus, of Reunion. But there are other
cases of genera which have facilities for a wider range,
but which for one reason or another (to be considered
later) have been unable to extend that range. The genus
Opisthocomus (containing by the way only a single species,
being the type of a distinct family) is limited to a portion
of British Guiana; the Gorilla to the forest tract of the
west coast of Africa; here again there is but one species.
Among families there are also a few with an exceedingly
restricted distribution. The Rhinochetide, containing only
one genus and species, R. jubatus, the Kagu, is only found
in the island of New Caledonia; the Trumpeters or
Psophiide are confined to certain districts of the Amazons,
and the four or five species of the genus might be quoted
as a case of very limited range in species. In Madagascar
the family Chiromyide is represented by but one species.
Cases of limited range among groups that may be regarded
12 DISTRIBUTION OF MONOTREMATA. (cH. 1
as higher than families are naturally not common. The
most striking perhaps is that of the Rhynchocephalia; this
group has but one species, the well-known Hatteria, which
is only found in a few small islands off the coast of New
Zealand. Not quite so striking from some points of view,
but perhaps more so in another, in that the group is a
higher one, is the case of the Monotremata; the two or
three genera are limited to certain parts of the Australian
region.
The facts just enumerated lead us to one of the
axioms of the science of Zoogeography, which was for-
mulated by Mr Sclater? in the following words. “Every
species occupies a definite area on the world’s surface; |
and: in like manner every genus and family, or other
higher assemblage of species, occupies a definite area on
the earth’s surface; or more shortly, locality or existence in
a certain spot is quite as much an attribute of animals as —
structure or the possession of a certain form or shape.”
The meaning of a restricted distribution.
It does not, however, by any means follow that this
area is now as it always has been. To study Zoogeography
properly a knowledge of the extinct forms of life is not
only desirable but necessary. By the aid of Paleontology
various facts, at first sight dark and meaningless, become
clear, or at least clearer. We must imagine each species
setting out from its centre of origin and gradually ex-
1 «The Geographical Distribution of Mammals,” Manchester Science
Lectures, 1875.
CH. 1] AREA INHABITED BY CHIMPANZEE, 18
tending itself by actual or passive migration right and left
and in every possible direction from this focus. Gradually
the form will be modified, or by competition or for some
other reason become extinct, leaving perhaps descendants
scattered here and there to tell the tale of a formerly wide
range. A guess can be made as to the comparative age of
a species or a genus by comparing such facts.
In all probability these instances of a restricted distri-
bution are to be explained in one of two ways; either the
form is a new one or it is an ancient one. A new species
recently come into existence would naturally, at least on
any theory of evolution, have a limited range because it
would have come into being at one locality and not have
had time to extend its range, supposing an extension to
be possible and not barred by impassable barriers.
The former alternative applies probably to most of the
examples that have been used, particularly perhaps to the
peculiar species often found upon oceanic islands, There
are however numerous species, as limited in their range,
which are in some cases certainly vestiges of races once
universally or widely distributed.
The Chimpanzee tribe is at present limited to the
forest region of central Africa. Its utmost range is nearly
across that continent. But the palaontological records of —
India contain a description and figures of a portion of a
skull evidently belonging to a chimpanzee which at one
time existed in India. Probably that indicated the high-
water mark of the extension of the chimpanzee, which has
since retired to more restricted boundaries. We know
from historical records that the lion used to occur in
14 SIGNIFICANCE OF LIMITED AREAS. [cH. I
Greece as well as in India and Africa, where it is now alone
met with. And at an earlier period still it was found in
this country. The hippopotamus, now limited to Africa,
was once found in Madagascar, and probably the same
species in Europe.
In such cases however the species in question are
generally also of generic, even of family, rank. The
remarkable lizard Hatteria, as already mentioned, is con-
fined to one or two islands off New Zealand; this lizard,
as the fossil remains of its allies tell us, is the sole survivor
of the Rhynchocephalia, a race of Saurians found in the
Mesozoic rocks of this country. The Viverrine Carnivore
Cryptoprocta, found at present only in Madagascar, is held
by some to be the last surviving remnant of the extinct
Creodonta; in any case it is generically distinct from any
other carnivorous animal. The same arguments may be
applied to the Thylacine of Tasmania, to the Aye-Aye
(Chiromys) of Madagascar, and to many other animals.
An apparently similar series of facts is therefore probably
to be explained in quite a different manner, an instance
of extremes meeting. The same mode of distribution
is indicative either of great antiquity or of extreme
modernity.
A comparatively restricted range however may be also
due to incapacity for migration. The converse is perhaps
more obvious. Widely distributed animals are either
flying animals independent of barriers which impede the
purely terrestrial species, or possess some special facilities
for voluntary or involuntary translation from country to
country. An entirely arboreal creature cannot pass across
CH. 1] DISCONTINUOUS DISTRIBUTION. 15
a level tract of country with no trees; nor can an
Amphibian whose skin requires to be kept moist cross an
arid desert. This consideration leads to an important
matter, the capacities for migration possessed by different
animals which will be discussed later.
Discontinuous distribution.
On the hypothesis that each animal has had its centre
of dispersal, that it came into existence once and at a
definite place, it is clear that originally at least the area
inhabited by a given species must have been perfectly
continuous. As a matter of fact it is generally the case ;
the remarkable thing appears to be not that there are
occasionally breaks in the continuity of the area inhabited
by a certain species but that it is so difficult to find
instances to illustrate the breaks. Mr Wallace explains
the rarity of discontinuous distribution among the species
of birds by the suggestion that they are possibly “more
rapidly influenced by changed conditions, so that when a
species is divided the two portions almost always become
modified into varieties or distinct species.” It must be
borne in mind also that birds are a modern group, and the
very difficulty of classifying them satisfactorily indicates
that there are but few breaks in the series; they are
possibly still in a condition of perpetual modification ;
they have not so to speak become fixed and crystallised,
like some of the older and in a sense more effete groups of
animals. However this may be, Mr Wallace quotes from
Mr Seebohm a highly remarkable instance of discontinuous
16 RANGE OF GENUS PERIPATUS. {cH. I
distribution in-a species of Tit. The Marsh tit, Parus
palustris, has a range nearly co-extensive with the
Palearctic region; but it is known throughout this
immense tract of country in certainly three varieties.
One of these is found in Southern Europe, in Italy,
Turkey, Greece, and Asia Minor. The same variety does
not crop up in the intervening country but again appears
in South China. Whether this variety is entitled to
specific rank or not, the fact is remarkable and really of
equal value. It almost suggests an explanation that has
been sometimes advanced to account for discontinuous
distribution in the species of Mollusca. No great diffi-
culty could be felt in the assumption that the same
variety had been twice produced in localities of a somewhat
similar climate. Mr Wallace refers to one or two other
examples of a somewhat similar nature; the Reed bunting
of this country reappears in Japan, being absent from
Asia. To take an instance from another class, Dr Scudder
records the existence of the butterfly @neis jutta’ in the
Rocky Mountains of British Columbia and in Hudson’s
Bay, and its absence from the intervening tract.
The genus Peripatus? offers an example of a genus
with an exceedingly wide and at the same time discon-
tinuous distribution. Peripatus is universally regarded
as a very archaic form of Arthropod, which has preserved
certain characters of the worm-like ancestor from which it
is presumed that the Arthropods have been derived.
There are, for example, a series of paired excretory organs
1 Butterflies of HE. United States,
2 Quart. Journ, Mier. Sci, vol. 28, 1888.
CH. I] RANGE OF PERIPATUS. 17
like those that occur among the segmented worms. On
the other hand it has the trachee of the tracheate
division of the Arthropods, and at least rudimentary
appendages of the Arthropod type. The genus has been
recently the subject of a careful monograph, so that we
are in possession of the facts of structure and distribution
of a good many species. Mr Sedgwick allows eleven
species as well founded, and there may be others. The
genus occurs in South Africa, South America and the
West Indies, in New Zealand and in Australia; one
specimen is found in Sumatra; otherwise it is absent from
the Oriental region. The species of the genus are mainly
distinguished from each other by the position of the
generative aperture, by the number and structure of the
legs and by colour. Mr Sedgwick divides them into four
groups which correspond to their range; the Australasian
species, for instance, form one group, the neotropical
another, and so forth. These four main groups are largely
separable on account of the varying position of the
generative pore, which may be between the last or the
penultimate pair of limbs or altogether at the end of the
body. There are differences too in the structure of the
generative organs, and the eggs show characteristic
variations; thus, in the Australasian species the ova are
large and full of yolk, in the Cape species though the ova
are large the yolk is not abundant, and finally in the
neotropical species of Peripatus the ova are quite minute,
and without food yolk. The single known species from
the Oriental region is more imperfectly known than many
of the others; but it seems to resemble the neotropical
B. Z. 2
18 DISTRIBUTION OF JAYS. [CH. I
rather than the Ethiopian species, which is not a little
remarkable. It has, as have the neotropical forms, the
generative openings between the legs of the penultimate
pair.
Separate areas of the species of a genus.
It sometimes happens that the area of distribution of
a genus is perfectly continuous but traversed by large
rivers or other checks to distribution. A genus occupying
a group of islands, for example, may be said to have an
unbroken range so far as is possible; but here under
similar circumstances it is frequently the case that the
isolation has been accompanied by the breaking up of the
genus into a number of species, perhaps corresponding
with the subdivisions of the area. The islands of the
group which together constitute the Sandwich Islands are
often inhabited by particular species belonging to a genus
common to the whole archipelago; the huge tortoises of
the Galapagos are in the same condition. A large tract
of country is often similarly inhabited by a series of
species belonging to the same genus; but each of these
keeps rigidly to its own particular territory: an inter-
mingling is rendered difficult perhaps by the infertility of
the species with each other, and partly also by the fact
that, the ground being already taken up, there is no room
for the inroad of a closely allied form, which has presumably
the same or nearly the same mode of life and would
therefore seriously compete. The twelve species of Jays
belonging to the genus Garrulus range over the greater
part of the Palearctic region; but nearly every species
CH. I] DISTRIBUTION OF RHEA. 19
has its own particular habitat, and does not interfere with
its neighbours. In the map which Mr Wallace gives in
illustration of the facts of distribution of this genus it is
seen that two species overlap just at the confines of
Europe and Asia, while the former of these, the European
Garrulus glandarius, is also overlapped by one species in
the south-east of Europe and by another in Algeria. It
is far more usual for species to occupy in common a given
area, than for a division of the territory to have taken
place. Nevertheless the example just quoted is by no
means unique, even among birds whose powers of flight
set ordinary barriers at defiance. But a rigid partition of
the area of a genus is more commonly met with among
animals which have not these exceptional means of
disposal. This will now be illustrated by three examples.
Distribution of Rhea.
The distribution of the species of Rhea! illustrates the
limitation of the species of the same genus each to its
own particular tract. The genus itself occupies a con-
siderable area of S. America, to which continent it is
absolutely confined. The three species of the genus have
been lately subjected to a careful comparison by Dr
Gadow, who has plainly differentiated the three recognised
species, viz. Rh. americana, Rh. macrorhyncha and Rh.
darwint. The anatomical characters which distinguish
them are not of course very marked, but they are amply
1 See Gadow, ‘“‘On the Anatomical Differences in the three species of
Rhea,” P.Z.S, 1885, p. 308.
2—2
20 THE SPECIES OF RHEA. (cH. I
sufficient for the purpose. Rh. darwini and Rh. americana
agree to differ from Rh. macrorhyncha in having only 15
(instead of 16) cervical vertebra and in having a broad
skull. They differ from each other principally in the fact
that the metatarsus in front has scutes on distal half only
in Rh. darwini; Bh. macrorhyncha agreeing with Rh.
americana in having transverse scutes along the whole
length of that part of the leg in front.
The range of the three is as follows :—Rh. americana
extends from Bolivia through Paraguay into Uruguay
and southward to the Rio Negro. Its head-quarters seem
to be the pampas of Argentina.
Rh. darwini is restricted to the eastern half of
Patagonia and to south-eastern Argentina. It overlaps
the last species about the Rio Negro.
Finally Rh. macrorhyncha occurs in the provinces of
Pernambuco and Bahia but does not overlap Rh. americana.
Dr Gadow intimates that on the whole Rh. darwin is the
best marked species. Hence possibly its overlapping is
less remarkable, since the greater difference in organisation
may go with a greater difference in habits.
Distribution of Ibexes.
There are altogether eleven species of Wild Goats as
allowed by Mr Sclater’, to which may be added a twelfth*.
(1) Capra pyrenaica, the Spanish Ibex, is not only
Pyrenean, but is found, slightly altered in character, in the
mountain ranges of other parts of Spain and Portugal.
1 P.Z.S. 1886, p. 314.
2 There are probably however more names than species.
CH. I] RANGE OF WILD GOATS. 21
“It is curious,” remarks Mr Sclater, “that it is more
nearly allied to the Caucasian ibex than to the ibex of
the Alps.”
(2) C. ibex, the ibex or steinbok found in the Alps
and Tyrol, but rare and needing artificial preservation.
(3) C. egagrus, the true wild goat, is probably the
origin of the domestic variety. It is now found only in
Crete and some of the smaller Cyclades as regards
Europe, but also extends through Asia Minor and Persia
to Sind and Baluchistan.
(4), (5) C. caucasica and C. pallasit are restricted to
the Caucasus, where they do not appear to overlap
greatly.
(6) C. sinattica. This ibex is found only in the
mountain ranges of Upper Egypt, the Sinaitic peninsula
and Palestine.
(7) C. walie is a distinct though rare and little
known species, from the highest mountain ranges of
Abyssinia.
(8) C. stbirica. It is remarkable that this species
should occur in two such distant localities as the Altai
mountains and the Himalayas. But it appears that a
thoroughly careful comparison of examples from the two
localities has not yet been made. This may very possibly
reveal differences.
(9) ©. falconerr. This ibex is popularly known as
the Markhore, it lives in the Pir-panjab and Sulaiman
ranges in Cashmere and Afghanistan.
(10) C. jemlanica. The “Tahr” occurs along the
whole range of the Himalayas.
22 WIDE DISTRIBUTION OF BEARS. [cH. I
(11) C. hylocrius. This species of wild goat. is
found in the Neilgherries and some other ranges of
southern India.
(12) C. severtzowt. This is another Caucasian
ibex which Dr Menzbier has added to the two already
referred to.
Here we have an instance of a genus of tolerably wide
distribution, but discontinuous. The discontinuity is
entirely due to the mode of life of the genus, which
frequents high mountains and cannot tolerate the level
plain. The mountains are comparable to oceanic islands
which can only be reached from time to time and under
favourable circumstances. This naturally results in the
isolation of those individuals which have migrated from
their original home to a neighbouring mountain range ;
and as a consequence of this isolation, which precludes
admixture with the parent stock, we have the production
of new forms, just as in the case of oceanic islands. With
this may. be compared the distribution of such a genus as
the giraffe, which has, or had until very recently, a range
of nearly the same extent as measured by miles. But
this range is uninterrupted by many tracts of country
that are uninhabitable to the animal; hence there are at
most two forms of giraffe. Even the true bears (genus
Ursus) may be contrasted. Dr Grevé allows nine species
and five varieties, hardly more than there are of goats.
But the range is enormously larger—nearly the whole
of Asia and Europe and nearly the whole of America—
and there is nowhere a gap of any kind,
CH. 1] SPECIES OF CASSOWARY. 23
Distribution of the Cassowaries.
The species of the genus Caswarius present an ex-
cellent instance of the specialisation of a genus when its
region is broken up by barriers into detached areas.
There appear to be altogether eleven or twelve species
of cassowary that are well, ascertained; there may even
be one or two more; at any rate there are more than
twelve names distributed among the cassowaries. I shall
not enter into the characters which distinguish the
species beyond remarking that they can be readily defined
by the shape of the “casque,” by the presence or absence
of wattles depending from the patch of naked skin upon
the throat and by the particular tints exhibited by the
generally brilliant colouration of the latter. The casso-
waries are entirely limited in their distribution to the
Australian region and do not range over the whole of that
region. They are absent from New Zealand and from
many other outlying islands. But although the cas-
sowaries are of bulky form and like other Struthious birds,
quite incapable of flight, they are by no means limited to
the continent of Australia itself. The following is a list
of the properly defined species and their range:
Casuarius australis, Australia.
C. picticollis,
C. Edwardsi,
C. Westermanni, New Guinea.
C. wuiappendiculatus,
C. Salvadori,
C. galeatus, Ceram.
24 CASSOWARIES OF NEW GUINEA. [CH. I
C. Beccarit, Wokan.
C. bicarunculatus, Aru.
C. Bennetti, New Britain.
. aa Tobi
C. occyntalis,
This case is analogous in many ways to that of the
goats already dealt with. Isolation has led to the
differentiation of species from a presumably identical
stock. Furthermore, where the area is large it has proved
capable of sustaining several species, which is not the case
with those islands of limited extent, such as Ceram, which
harbour cassowaries. With this fact may be compared
the presence of only a single species of Ibex in the com-
paratively small tract of country occupied by the
Pyrenees, and the presence of this species in the more
' extensive Caucasus. The existence of five out of the ten
species in New Guinea marks this large island out as the
head-quarters of the group from whence they have
migrated elsewhere, or perhaps, if the islands are to be
regarded as a broken continent, have been isolated.
That New Guinea is to be regarded as the original home
of the cassowaries is perhaps also shown by the fact that
the species now existing there present in themselves most
of the important modifications of structure which the
genus exhibits. In his most recent revision of the
cassowaries Mr Sclater divides those without watiles
from those which have these appendages. Both kinds
occur in New Guinea. On the other hand this con-
1 The editor of the Ibis (Oct. 1894, p. 560) is inclined to doubt the
distinctness of these two species.
CH. 1] DISTRIBUTION AND STRUCTURE. 25.
sideration is to be qualified by the fact that no casso-
wary with a laterally compressed casque (another
character made use of by Mr Sclater) exists in New
Guinea. In all the New Guinea species the casque is
transversely compressed.
Classification and Distribution.
The facts of distribution are constantly liable to be
misunderstood through ignorance of classification. Not
only is a serious error in the actual facts of the distribution
of a particular group caused by wrongly assigning to it
some individual genus or species, but the significance
of the facts is by this largely, sometimes totally, obscured.
A knowledge of comparative anatomy is absolutely
essential to the student of distribution. It used to be
supposed that the central American Carnivore Bassaris
was a member of the family Viverride; the genus
therefore was believed to be the only Viverrine found in
the New World, a singular anomaly in the distribution of
the group. But Sir William Flower in his paper upon
the skull in the Carnivora showed that this animal is
really an ally of the Raccoons, which are purely an
American family. Everybody is acquainted with the
fact that monkeys are found both in the old world and in
the new. But the fact gets a far larger significance when
it is realised that the new world monkeys form a group
by themselves which differs from that of the old world
monkeys in a number of important anatomical characters.
The wide distance and the absence of means of transit
26 WIDE RANGE OF ANCIENT FORMS. [cH. I
within recent times has brought about the great diver-
gence which is now seen between the two sections of the
Primates, the new world Platyrrhines and the old world
Catarrhines. It has been already pointed out in dealing
with the distribution of the archaic Peripatus that the
species of different parts of the world form natural
assemblages separable from those of other parts of the
world by definite anatomical characters. This is the case
too with many other genera and families of animals. We
invariably find ‘that when a group, which Palzontology—
or in the absence of direct evidence from fossils, other
considerations derived from anatomy or embryology—
proves to be an ancient group, has a tolerably wide and
discontinuous distribution, marked differences in structure
distinguish its representatives in different parts of the
world. This is more marked still in the case of a group
which has but limited powers of dispersal. We shall now
illustrate the connection between distribution and ana-
tomical structure by a few examples, which are of course
few among many; in other pages other instances have
been or will be treated of and reference may be made to
those places for further illustration of the general fact.
Distribution of the Gallinaceous birds.
The Gallinaceous birds (Alectoromorphe of Huxley)
offer an exceedingly instructive example of the connection
between anatomical structure and geographical distri-
bution. There can be no doubt that this group is a
natural one. It is divisible into the following seven
cH. 1] THE GALLINACEOUS BIRDS. 27
families!:—Grouse, Turkeys, Guinea-fowls, Pheasants,
Megapodes, Curassows and the aberrant Hoatzin (Opis-
thocomus). They are thus distributed:
1. Tetraonide (Grouse). Palearctic and Nearctic.
Phasianide (Pheasants). Oriental.
Numidide (Guinea-fowls). Ethiopian.
Meleagrida (Turkeys). Southern Nearctic.
Cracidee (Curassows). Neotropical.
Megapodidee (Mound-builders). Australian.
7. Opisthocomide (Hoatzin). Neotropical’.
They are not, however, in every case absolutely confined
to these regions as defined by Mr Sclater. Thus among
the Megapodes one species gets into the Indian region,
and the Phasianide stray into the Palearctic. The
Tetraonide are really almost cosmopolitan, though mainly
massed in the two northern regions of the earth’s surface.
The Curassows extend into the southern parts of the
Nearctic, occurring as they do in Mexico and in California.
Such briefly are the facts of the distribution of this group
of birds; it now remains to enquire into the mutual
relationships of the several families or subfamilies. Mr
Huxley unites the Megapodes with the Cracide into
a group Peristeropodes, and separates them from all the
rest which constitute his Alectoropodes. The former
division has a sternum with less deeply marked notches,
the vomer is well-developed, and the hallux is attached to
the foot on a level with the other toes. These characters
look as if they were more primitive than the deeply
O om Ww Lo
1 P,Z.S. 1868.
2 These terms are explained later; see Chap. II.
28 STRUCTURE OF GALLINACEOUS BIRDS. [cH. I
notched sternum, the more rudimentary vomer, and the
abnormal position of the hallux in the Alectoropodes.
This is very likely so, but as Fiirbringer’ has pointed out,
the structure of the soft parts of the Megapodes are more
different from what is found in the Curassows. The latter
often have a convoluted windpipe, which does not occur
in the Megapodes, but is met with in some Guinea fowls
and in the Grouse (Tetrao wrogallus). The Megapodes
have lost one of the two carotid arteries, and their oil
gland has not the tuft of feathers found in other Galli-
naceous birds; in fact, as regards internal structure other
than that of the skeleton, the Cracide are not so very
near to the Megapodes. All these structural features
will seem perhaps of small moment to the student of
invertebrate anatomy; but it must be remembered that
birds form a very circumscribed group; the anatomist
is glad of the smallest characters upon which to found
differences; and the differences enumerated are not small,
considering the characteristics of the order. Apart, how-
ever, from these differences it does appear the two families
Cracidee and Megapodide are the most primitive Gallin-
aceous birds now in existence; not only do the two
points referred to above tend to show this, but we might
also perhaps urge the “reptile-like habit” which the
Megapodes have of laying their eggs in a heap of dead
leaves and abandoning them to the kindness of nature—
a habit which of course recalls that of nearly all Reptilia.
Moreover neither the Curassows nor the Mound-builders
show to anything like so great a degree that difference in
1 Untersuchungen zur Morphologie der Vigel.
CH. I] FOSSIL REPRESENTATIVES. 29
plumage between the sexes which is often developed to so
extraordinary an extent in the other members of the
group. In many birds which are presumed to be of an
ancient type, for instance the Ostrich tribe, there is the
same absence of strongly marked secondary sexual
characters in colouration. In this particular enquiry we
cannot unfortunately get any assistance whatsoever from
Paleontology; the only fossil Megapode recorded in
Lydekker’s Catalogue of Fossil Birds is Talegalla
lathami, a species now living; there is no information
as to extinct Cracide. The Alectoropodes on the other
hand, are much more nearly connected among themselves.
Fiirbringer, indeed, does not divide them further‘. The
Guinea-fowls perhaps are the most distinct group; but
the Argus, Pheasant and the Peacock are looked upon
by Fiirbringer as somewhat intermediate between them
and the more typical Phasianide. About this group of
Gallinacee there is some paleontological information ; a
few existing species (Lagopus albus, Francolinus pictus)
have been described from the Pleistocene of Europe
and India respectively; the extinct genus Palwortyz,
“ Partridge-like birds,” containing eight species, occurs in
the Eocene and Miocene of Europe; three species of an
allied genus, Palwoperdix, are also found in the Miocene
of Europe; five species of Phasianus have been found in the
Pliocene and Miocene of Europe; four species of Gallus
occur in the “superficial deposits” of New Zealand, the
“Cavern-deposits of the Lahn valley, Germany” and the
Pliocene of France; of greater interest is the genus Tao-
1 Nor Gadow with any confidence, see Bronn’s ‘‘ Thierreich.” Aves.
30 CRACIDEZ AND MEGAPODID. [cH. I
perdix (one species only), from the Eocene of France,
which is said to present affinities with Nuwmida and
Meleagris, ie. with African and American forms. The
facts which have so far been enumerated enable us to
draw some interesting conclusions; the first is indis-
putable; each of the great divisions of the globe is
tenanted by a special group of Gallinaceous birds, which
is with the exception of the nearly cosmopolite Tetraonide,
confined to that particular region, There are some
reasons for considering that the cosmopolitan Tetraonide
are of a less ancient stock than the restricted Cracide and
Megapodide. There is a closer structural connection
between the Gallinaceous birds of the three great con-
tinents of Europe, Africa and Asia, than between any one
of them and the Gallinaceous inhabitants of South
America or remote Australia. The two latter regions,
being truly the ends of the earth, are populated by the
two most ancient types of Gallinaceous bird, which how-
ever are not very closely allied.
In a very tentative way we may point out another
possible conclusion. We may presume that the earth
was possessed, as regards Gallinaceous birds, by an ancient
stock of which the Cracide and Megapodide are the only
survivors; later on, from the ancient stock, arose other
families which increased and multiplied so much as to
drive their forerunners into the more remote corners,
where an inroad of the sea preserved them from further
competition; as the remnants of the more ancient
race came thus to be widely separated and exposed to
divergent conditions they would naturally get to be more
CH.I] RANGE OF SLOTHS AND ANTEATERS, 31
and more unlike each other; hence the differences between
the Cracide and Megapodide. We find in fact the
presumably younger race spreading over the whole earth,
while the remnants of the older race are limited to the
more remote parts. All this fits in well, as will be
remarked later, with the Polar theory of the origin of life.
Distribution of the Edentata.
The Edentata are a group of mammals in which
the distribution has a very strong relation to anatomical
structure. That there is this intimate connection has
been shown by recent anatomical investigation, which
is summed up and its purport explained in a paper by
Sir William Flower‘, from which the information upon
the subject can be most conveniently got. Formerly the
members of this group were divided into families not at
all consistent with deep lying structure but rather with
superficial modification depending upon similar habits
and ways of life. Before examining the rational classifi-
cation of the group as proposed by Sir William Flower,
it will be convenient to briefly pass in review the different
genera and families into which the Edentata may be
divided.
The living members of the group readily separate into
five families, which are the following :—Bradypodide, or
sloths, containing the two genera Bradypus and Cholepus.
Myrmecophagide, or anteaters, with the genera Myr-
mecophaga, Tamandua and Cycloturus.
Dasypodide, or Armadillos, with the six genera,
1 P.Z.S. 1882, p. 358.
32 OLD WORLD EDENTATES. (cH. I
Tatusia, Dasypus, Xenurus, Priodon, Tolypeutes and
Chlamydophorus.
Manide, or scaly anteaters, with really only one genus
Manis, though more have been allowed by some system-
atists.
Orycteropodide, or Cape anteaters, containing but a
single genus Orycteropus.
Now it has been customary to associate together
the anteaters of both the old and the new world, sepa-
rating them on the one hand from the sloths and on the
other from Orycteropus. We thus get a group ranging
over South America, the greater part of the Oriental
region, and a large tract of the Ethiopian region, for
Manis is found in both of the Jast named regions. The
Manis of the old world has a strong superficial likeness to
the anteaters of the new world. The same long tongue
and well-developed salivary glands are present in both,
while neither of them have any teeth; correlated with
this likeness in structure is the fact that both feed upon
ants. The Australian anteater, Echidna, was on this
account placed by Linneus in the same preat group
as that containing the Edentata; it has in the same way
a long tongue and well developed salivary glands. There
is, however, of course no intimate connection between the
animals; we have here merely a case of modification to
the same end, the utilising of an abundant ant or termite
supply. The Woodpecker and the Chameleon show a
remarkably analogous modification of the alimentary
organs. This is really the only reason, apart perhaps
from a general similarity in form, which has led to the
‘VIVINSGS JO NOILNEIYLSIC
CH. I] STRUCTURE OF EDENTATES. 33
uniting of the Old World with the New World anteaters.
But an examination of other structures does not show
any likeness between the Manis and the Myrmecophaga,
but does reveal an unmistakeable resemblance between
the latter and the sloth, to which it is so unlike in
external form and in habits. In the American anteater
the vertebre to a large extent interlock with each other
by an additional series of articular processes, not found
in other mammals, excepting only the Dasypodide, and
the extinct Megatheriide, and which is to a less extent
but still obvious in the sloths. This structural resem-
blance found in animals of such diverse habit must have a
significance in considering their affinities. The fact that
the processes in question are in a rudimentary condition
in the sloths is correlated with the fact that in those
animals which depend from the branches of trees, and use
the muscles of the back but little, the articular processes
generally of the spine are poorly developed; the fact is
they are of even greater importance as evidence of real
blood relationship. As Sir William Flower says, the fact
may be almost said to prove “that the sloths are
descended from animals in which they existed in a fully
developed form.” Neither in Manis nor in Orycteropus’
are there the slightest vestiges of these additional articu-
lar processes. It is also pointed out that the shape of the
sternum is characteristic of the New World and the Old
World Edentates respectively. When we come to other
details of structure there is the same alliance to be noted
between the various families of Edentata found in America,
more particularly is this to be seen in the anatomy of the
B. Z. 3
34 EXTINCT EDENTATES. [cH. I
reproductive organs. On the other hand, the Oryctero-
podide are not so nearly allied to Manis as are the
different genera of New World Edentates among them-
selves. But though this is the case it does not show
any special affinities with the New World forms. It may
be temporarily regarded as a distinct family having
(at present) problematic relations to the Manide, which it
resembles by what are principally negative characters.
The placenta is an organ which is of great assistance
in bringing out affinities between various groups of
mammals; unfortunately it is not known whether the
placenta of Orycteropus is deciduate or the reverse; if
non-deciduate there is a likeness to the Manis and not to
the New World Edentates. At any rate it is clear that
Manis, even if it be not a close ally of Orycteropus, is still
further removed from the Myrmecophagide, Dasypodide
or Bradypodide. <A glance at the structure of the fossil
members of the order entirely confirms the broad lines
of classification thus laid down by Sir William Flower.
The Megatheriide are in some respects intermediate
between the anteaters and the sloths; the teeth are those
of the sloths, but the diminution of their number in
the genus Celodon “leads towards their total suppression
in Myrmecophaga.” The lengthening of the skull in
Megatherium is another step in the direction of Myrme-
cophaga. On the other hand the Old World Edentates of
the tertiary period, so far as they are known, lend support
to the view that they are more nearly related to the
existing Edentates of that part of the world. We have
therefore in this group the closest relation between the
CH. I] DISTRIBUTION OF CUCULIDZ. 35
geographical range of its members and their structure;
there is no confusion possible between the anteaters of
the Old World and those of the New, while, unlike though
they are outwardly, all the Edentata of the New World
form a natural assemblage; the Edentata of the Old
World form perhaps two natural assemblages of equal
value to the one of the Old World, but there is no hint of
any special resemblance between either and the New
‘World group.
Though the Gallinacez and the Edentates thus show
a decided relation between distribution and structure, the
same is not the case with other plentifully distributed
groups of birds.
Distribution of the Cuckoos.
The cuckoos will serve as an instance to the point.
This family has been investigated anatomically! to as
great an extent as the Gallinaceous birds ; and the mutual
affinities of the numerous genera is to some extent plain.
Fiirbringer is of opinion that the genus Phwnicophaés
represents more nearly than any other existing form the
primitive cuckoo. This is chiefly on account of the fact
that it possesses the complete muscle formula, none of the
typical muscles of the thigh being absent, and has a
syrinx constituted on what must be regarded as the
typical plan for birds, viz. the “tracheo-bronchial.” The
remaining genera have diverged from this in two ways ;
either the accessory femoro-caudal muscle has disappeared,
1 See Beddard, P.Z.S. 1886. i
' 3-2
36 OLD WORLD AND NEW WORLD cUCKOos. ([CH. 1
or the voice organ has moved down the bronchus pro-
ducing that form of syrinx known as the “bronchial.”
These two changes have in no case occurred simul-
taneously. We find either the one or the other. But
there is no correspondence between the change in
structure and range in space. In both the Old and
the New World we meet with cuckoos like Crotophaga
and Geococcyx (America) and Centropus (Old World) in
which the syrinx is bronchial and the muscles all present.
In both hemispheres are cuckoos like our common
Cuculus canorus and the American Piaya, m which the
trachea has retained the typical form, while the accessory
femoro-caudal muscle has completely vanished. If M.
Milne-Edwards is right in identifying a fossil cuckoo from
the Miocene of France as a Coucal (Centropus) the
problem is not rendered any easier. It shows, however,
that at this period the two main divisions of the family
were differentiated in Europe, whence they may have
spread over the world. It must be noted that the genera
of the New World are nearly all distinct from those of the
Old World, and that it is possible, so far as our present
knowledge goes, to distinguish into sub-families by the
differences in the arrangement of the feather tracts the
New World from the Old World representatives of the
two chief subdivisions of the group. This affords an
example of a frequently recurring series of facts. It is
not of any interest to point out that the American genera
are in every case distinct from the African or Indian
genera and then to leave the matter. We have to account
for, or to attempt to account for, the mutual relationships
CH. I] FOSSIL CUCKOOS, 37
between the genera of the different parts of the world.
So far as our knowledge of living cuckoos goes the facts
have no significance in this connection. Presuming with
Wallace that they originated in the tropics of the Old
World and thence spread to the New World we have the
remarkable fact that in the lengthy journey to South
America the two main types already differentiated before
migration took place, have been equally successful in
colonisation, and have advanced equally far. Fiirbringer
holds, and with some justice, that a country inhabited by
the oldest form of the group in question is more likely
to be its original habitat than elsewhere. In this case
Wallace’s view that the cuckoos sprang into existence in
the Oriental region is supported. But quite recently the
whole matter has been put in a rather clearer light.
Milne-Edwards has found’ the remains of a cuckoo which
he has relegated to a new genus and which he is unable
to distinguish from the living Phawnicophaés. In this case
Fiirbringer’s belief that Phaenicophaés is the nearest
approach to the archetypal cuckoo is to some extent
justified ; and we have a family formerly of wide range,
which is a further proof that it is an ancient form.
Moreover if we can now assume that the parent stock
of the cuckoos was differentiated in Europe and thence
spread over the New as well as the Old World, the
difficulties in the way are at least rendered less.
We shall now indicate briefly the distribution of a few
of the principal groups of animals. The mammals and
1 Comptes Rendus, 1894,
38 DISTRIBUTION OF TORTOISES, [cH. I
birds are dealt with later in giving the characters of the
different regions and sub-regions.
Distribution of Chelonia.
When Mr Wallace wrote his text-book upon Geo-
graphical Distribution he was able to make but few
remarks upon the distribution of the Chelonia, since the
classification was in a very imperfect state, and therefore
the bearing of the facts of distribution were not apparent.
Now however, thanks to Mr Boulenger’s catalogue of the
order, we are in a position to deal with the distribution of
the group in a manner more satisfactory than was open to
Mr Wallace.
Mr Boulenger divides the Chelonia primarily into two
great groups, the Athecz and the Thecophora. The first
group is distinguished by the fact that the vertebre
and ribs are free and not connected with the bony
exoskeleton. As it only contains a single family, genus,
and species, Sphargis coriacea of entirely marine habitat,
it need not concern us any further here. The second
division of the Chelonia is made up of three super-families,
the Cryptodira, the Pleurodira and the Trionychoidea.
These together contain eleven families, of which there are
seven in the Cryptodira, three in the Pleurodira and only
one family in the Trionychoidea.
Of the first super-family the families Chelydride (two
genera), Dermatemydide (three genera), Cinisternide
(one genus) are confined to the American continent. The
Platysternide (one genus) range over S. China, Siam and
Burma; there is but a single species which has this wide
CH. I] DISTRIBUTION OF TORTOISES. 39
range. The Testudine is by far the largest family of the
Chelonia; Mr Boulenger divides it into 20 genera,
containing between them 113 species which are cos-
mopolitan with the exception of Australia and Papuasia.
Eleven of these genera are Oriental in distribution.
Three are American only. One, Pixys, is confined to
Madagascar. Two are confined to Tropical and Southern
Africa. Three have a wide range over both the Old and
the New World; among these is the genus Testudo which
includes the gigantic tortoises of the Galapagos and the
Mascarene islands. The last family is exclusively marine
and may therefore be left out of consideration.
The Pleurodira contains, as already said, three families.
The Pelomeduse have a curious distribution ; its three
genera, Sternotherus, Pelomedusa, and Podocnemis being
found respectively in Tropical Africa and Madagascar,
Africa and Madagascar, South America and Madagascar.
The family Chelydidz contains eight genera. Of these
five are South American ; two range through Australia and
New Guinea, while one, Hiseya, is only Australian. The
family Carettochelydide contains but a single genus
and species found only in the Fly river in New Guinea.
The Trionychoidea includes only one family which is
made up of six genera. Of these three are East Indian,
two tropical African, while the remaining genus Trionyx
ranges through Africa, Asia and North America,
It is obvious from the above summary which I have
made complete, owing to the advantage of having
Mr Boulenger’s list, that South America is the principal
home of the land and fresh-water tortoises. The American
40 DISTRIBUTION OF LACERTILIA. [cH. t
continent has altogether fourteen peculiar genera. The
Oriental region which comes next has fifteen peculiar
genera. It may be thought that the Oriental region ought
to have been placed first; but it seems less important than
the Neotropical, inasmuch as the latter region has a larger
number of peculiar families. The resemblances shown
between South America and Madagascar (in the case of the
genus Podocnemis) is noteworthy, and has been commented
upon elsewhere. The Australian region is poor in tor-
toises ; it has only three genera, of which, however, one is
the type of a special family, confined to New Guinea.
Africa is also poor; it has but seven peculiar genera, of
which several range also into Madagascar, and one is
limited to that island.
The group also shows some remarkable instances of
discontinuous distribution. The Chelydide are limited to
the Neotropical and Australian regions ; but, as Mr Blanford
points out, this is to be possibly explained by the fact that
members of this family are met with in a fossil condition
in Europe. It will have been noticed that they are
totally absent from New Zealand.
Distribution of Lizards.
In this group again the facts have been collected by
Mr Boulenger in his British Museum catalogue. The
genus Hatteria is excluded from the Lacertilia; the facts
of its distribution have been already considered. The
true Lizards contain altogether, according to Mr Boulenger,
twenty families. Of these only two approach to being
cosmopolite, the Geckotide and Scincide ; but the former
CH. I] THE RANGE OF CHAMZLEONS. 41
appear to be often accidentally conveyed on ships, which
at least shows that they have facilities for becoming
cosmopolite ; also they have many archaic points in their
structure which point to a long existence in the world.
The vertebre are biconcave and have considerable
remains of the notochord between the centra; this is a
character which occurs in many ancient forms of vertebrates,
Though there are not any other families of Lizards which
are so widely spread as those which have been just
mentioned there are a few others which have a moderately
wide range. This may perhaps be partly attributed to
the small size as a rule of the lizards and perhaps to their
largely insectivorous habits, which renders them more
independent of locality, than if they were vegetarian.
The fact that many occur upon oceanic islands is a fact
which shows that they have greater powers of dispersal
than many other groups of animals, and at the same time
necessarily renders the study of their distribution less
interesting.
The families Eublepharide, Iguanide, Anguide, Am-
phisbeenide, and Anelytropide are found in both the Old
and the New Worlds. The bulk of the Iguanide are,
however, tropical American, and are very characteristic of
the region. The Chameleons have a distribution which is
remarkably parallel, as M. Trouessart has pointed out, to
that of the Lemurs. The bulk of them are found in
Madagascar only, but they also range into Africa and the
East Indies. Their arboreal habits, as also in the case of
the Lemurs, is perhaps to be compared with their
comparatively limited range. A very characteristic Old
42 MONITORS. (CH. I
World family is that of the Monitors (Varanide); there
are a large number of species which range over the
Oriental, Ethiopian and Australian regions; the group
comprises some of the largest of lizards, and some of them,
such as the Nilotic Monitor which lives upon the eggs and
young of the Crocodile, are aquatic in their mode of life.
The structure of the Monitors is such as to separate them
very widely from other lizards; but they have no
particular relationship, as was at one time held, to the
peculiar American family of the Teiide, of which the
Teguexin is an example. The Lacertide are also a
peculiarly Old World family. To them belong two out of
the four indigenous lizards of this country. The fourth,
the Blind worm, is the representative of the family
Anguide. The most limited range of any family is
afforded by the Helodermatide, containing but one genus,
Heloderma, the Gila monster of the state of Arizona.
With one possible exception, it is the only poisonous
lizard. Australia has one peculiar family of lizards, the
Pygopodide. America has two others besides those
mentioned, viz., Xenosauride and Xanthusiide. The
distribution of the lizards undoubtedly shows a marked
difference between the Old and New Worlds. Moreover the
Old World is more logically to be divided perpendicularly
than horizontally according to Dr Giinther. He would
divide the world into six regions, (1) America, (2) Africa
and Europe, (8) India and the Mantchurian sub-region of
the Palearctic, (4) Madagascar, (5) Tropical Pacific, and
(6) New Zealand, characterised of course as far as the
true lizards are concerned by negative characters. It is
CH.1] AFFINITY BETWEEN AFRICA AND EUROPE. 43
interesting to notice that the lacertilian fauna of Africa
attaches itself to that of the western Palearctic region; it
has often been remarked that Europe is really African in
its affinities; this however has been to a large extent
disguised by the destruction of animal life or its removal
due to the glacial period. It will be remembered that
before the glacial period and during ‘the interglacial
periods (?) there were Hippopotami, Hyznas &c. in
Europe. Mr Boulenger unites Australia with the Oriental
region, an union which is confirmed by the consideration
of other groups of animals of some age, e.g. earthworms
and crocodiles, and is accepted by botanists.
The Distribution of Crocodiles.
The distribution of the Crocodilia is very interesting,
and on the whole fits in with the known laws of the
distribution of animals. Fortunately one of our foremost
authorities on the system of reptiles, Mr Boulenger, has
recently summed up the existing knowledge of the range
of the group in the British Museum Catalogue. He
allows seven genera, Gavialis, Tomistoma, Crocodilus,
Ostoleemus, Alligator, Caiman and Perosuchus. There are
eleven species of Crocodilus, three of Alligator, and five
of Caiman; the remaining genera consist of a single
species apiece. As might be supposed from the large
number of species into which it is divisible, the genus
Crocodilus has the widest range of all the Crocodiles. It
occurs in all the tropical regions of both the Old and the
New World. Alligator was believed until recently to be
confined to America; but the existence of a Chinese
44 DISTRIBUTION OF CROCODILES. (cH. I
species, A. sinensis, was made known in 1879. The
Caimans and Perosuchus are exclusively tropical American.
Ostolemus is West African. Gavialis is confined to some
of the rivers of India, while Tomistoma has only been met
with in Borneo.
Though the two latter genera by their elongated
snouts suggest the Mesozoic Teleosaurians, it seems
probable that Caiman and Perosuchus represent the
most archaic among the existing Crocodilia. The reason
for this opinion is that they alone possess a ventral as well
as a dorsal armature of scutes, such as were developed in
forms like the Wealden Bernissartia, in which the ancestor
of both Crocodiles and Alligators is seen by some. Toa
feeble extent the ventral scutes are to be found in
Alligator, and also apparently in Ostolemus. This, it
will be noticed, is quite in accord with the wide but
discontinuous distribution of those genera, which might
almost on. this account be put into a separate family. The
presumption would be that formerly they were more
widely spread, but that the process of time produced gaps
in their ranks, leaving the present detached fragments.
The existence therefore of an Alligator in China is not so
remarkable if this point of view be borne in mind.
As to the true Crocodiles of the genus Crocodilus, they
are characterised also by the fact that there are constantly
fifteen teeth only in the lower jaw; the old idea that a
Crocodile could always be distinguished from an Alligator
by the fact that the fourth tooth in the lower jaw was
received into a notch instead of into a pit in the upper
jaw has been exploded by the discovery that in an
CH. 1] CROCODILES OF OLD WORLD. 45
undoubted Crocodile, C. palustris, both conditions may
occur. The reduced number of teeth is another indication
of the more modern character of the genus Crocodilus.
The wide distribution of the genus is indicative of a
younger and more vigorous stock, as is also perhaps the
larger size of many Crocodiles as compared with Alligators.
In Mr Boulenger’s catalogue the measurement of no
Alligator is stated to exceed 44 metres, and they are
generally much smaller than this;.on the other hand the
Crocodile of Madagascar is said to reach a length of
thirty feet, and generally the Crocodiles are large. If
this view respecting the geographical and structural
relations to the Crocodilia be the correct one it is
significant that in this case as in so many others the
archaic forms have chiefly gravitated towards South
America.
The bearing of the facts in the distribution of this
order upon the generally recognised zoo-geographical
regions seems to comply with a primary division of the
earth’s surface into Paleogea and Neogea; there is
apparently less difference between the Oriental and
Australian regions than between either of them and the
Ethiopian, though the difference here is but slight.
The fact that Crocodiles can traverse the sea is
perhaps partly responsible for the absence of peculiar
types in the Australian continent, which is connected
with Asia by so many intervening islands. It is also
perhaps a testimony to the age of the group as contrasted
for example with the more modern mammals and birds.
46 RANGE OF COLUBRINE SNAKES. [cH. I
The Distribution of Snakes.
The following account of the range of this order will
be limited to the Colubrine section, smce Mr Boulenger’s
catalogue, whence my information is derived, has not yet
reached the Vipers. The Colubrines, which are chiefly
though not entirely non-venomous serpents, may be divided
into seven families, the Typhlopide, Glauconiide, Boide,
Tlysiidee, Uropeltide, Xenopeltide and Colubride. Two
of these families, the Uropeltide and Xenopeltide, are
entirely confined to the Old World; the former family
contains only seven genera of burrowing snakes which are
limited in range to Ceylon and other regions of India.
The Xenopeltide is a still smaller family, for it contains
only a single genus and species, which occurs in S. E. Asia.
The other families are more or less cosmopolitan. The
two largest of these are the Boide and the Colubride.
The Boide are again subdivisible into two groups, the
true Boas and the Pythons. The latter are nearly entirely
Old World in habitat, the only exception being the Mexican
Loxocenius. On the other hand the Boine are nearly as
exclusively American; out of the thirteen genera which
Mr Boulenger allows in the sub-family six are purely
American, one belongs to the Australian region, one is
common to Asia and Africa, and two genera, Casarca and
Bolieria, consisting of a single species apiece are restricted
to Round Island near to Mauritius; there remain the two
genera Corallus and Boa; these are remarkable for the
fact that while both are almost entirely American or
Antillean in range they contain one or two species which
CH. 1] FROGS AND TOADS. 47
are found in Madagascar, a state of affairs which is paral-
leled in some other groups.
On the whole the snakes emphasise the necessity of
drawing a sharp line between the Old and New World, as
indeed do all the reptiles.
Distribution of Batrachia.
While the Urodele Amphibia are limited to the
northern hemisphere, the frogs and toads have a nearly
world-wide range ; the only places where they are uniformly
rare are true oceanic islands; as will be explained, facilities
for crossing the sea are entirely wanting. The occurrence
therefore of a true frog in the Solomon islands is one of
the chief proofs, from the zoological side, that this island
is not a real oceanic island ; a species which occurs in that
island (there are eight others) is the largest of all existing
frogs and toads and is known as Rana guppyi. The Fiji
islands possess three species of the genus of frogs Cornufer.
This family, the Ranidz, is nearly cosmopolitan; but the
toads comprised in the family Bufonide are more nearly
completely cosmopolitan. The tree frogs, Hylide, are also
very widely distributed ; but as is natural they find their
greatest. development in “ Dendrogea,”’ the Neotropical
region. Oddly enough these often purely arboreal crea-
tures, some of which do not even lay their eggs in pools,
are totally absent from the forests of Africa, indeed from
the Ethiopian region altogether. The lowly organised
group of frogs, Aglossa, comprise two families, the Pipide
and the Dactylethride; the latter are in more than one
particular near to the tailed Amphibians; they are, for
48 FAMILIES OF BATRACHIA. [cH. I
instance, more thoroughly aquatic than the Ranide; they
sprawl about awkwardly on land instead of sitting up in
the alert though broken-backed fashion of other frogs ;
the eggs too are laid not in masses as are those of the
common frog, but singly as in the newt. This family is
restricted to tropical and southern Africa; the Pipide
including only the genus Pipa, in which the female
harbours the young in holes in the skin, is Brazilian.
Two families, Amphignathodontide and Hemiphractide
are peculiar to the Neotropical region. The family of the
Cystignathide are remarkable in being found in the
Neotropical and Australian regions; the family contains a
large number of species of which several have the habits
of the tree frogs; and one genus has been on this account
termed Hylodes. A very characteristic member of this
family is the “Barking toad” of South America, Ceratophrys
ornatus, of which specimens may be always seen at the
Zoological Society’s gardens. Another instance of discon-
tinuous distribution is offered by the family Discoglosside,
which occurs in all the sub-regions of the Palearctic
region and has a single representative in New Zealand,
viz. Liopelma hochstetteri. Resemblances between South
America and Madagascar are shown here, as in some other
groups of the animal kingdom. The family Dendrobatide
are represented by two genera Mantella and Stumpffia,
comprising five species, in Madagascar, and by the genus
Dendrobates in South America. On the whole the Neo-
tropical region is most abundantly inhabited by peculiar
forms. Out of the fourteen families allowed by Mr
Boulenger no less than ten are found in that realm and.
CH. I] BATRACHIA OF MADAGASCAR. 49
as already mentioned four are absolutely confined to it.
No other region has more than seven of the families
found in it. And the Ethiopian is the only other region
which has a family all to itself, viz. the Dactylethride.
The Ethiopian and the Oriental regions are allied by
their Batrachian fauna. Madagascar for example shares
with the Oriental region nearly all its genera; the Ranid
genus Rhacophorus is characteristic of the east, where it is
represented among other species by the flying frog, R.
reinwardti, the size of whose hind limbs and the amount
of webbing between them is said to have increased
progressively in illustrations of the animal. The family
Discophide is limited to these two regions; indeed but
for a single Burmese species it is purely Mascarene.
The Distribution of Scorpions.
It is greatly to be wished that other specialists would
do as Mr Pocock has done and put together a brief account
of what is known respecting the geographical range of
their groups. In a recent number of Natural Science?
we have an epitome of the distribution of scorpions.
The existing genera, 60 in number, are divided among
eight families. All of these are tropical or sub-tropical in
range. No scorpions are found in the more northern
latitudes and they are entirely absent from New Zealand.
On the other hand they occur in Patagonia. In Europe
the northernmost limit is the south of France and the
shores of the Mediterranean generally. In Asia lat. 40°
1 May, 1894.
B. Z. 4
50 DISTRIBUTION OF SCORPIONS. [cH. I
marks their northern limit. In America they do not,
according to Mr Pocock, get quite so far north as this.
Although the scorpions are an extremely ancient race,
beginning in the Silurian, and occurring there and in the
Carboniferous in, the. shape of forms which hardly differ
from existing species, thé modern ‘répresentatives show a
range which corresponds with that of existing continents.
The existing scorpions are nearer to the carboniferous
Anthracoscorpii in that the feet terminate in two claws
instead of in the single claw of the Silurian Palwophonus,
which Thorell has relegated to another group, the Apoxy-
podes, reserving the name Dionychopodes for the others.
Mr Pocock deduces from a comparison of the slight differ-
ences in structure between the ancient and the modern
forms certain facts of structure which may be looked upon
as archaic; though these seem to those accustomed to the
structure of other groups very minute it is evident that
we must be content with them owing to the already
mentioned homogeneity of the group. In the most ancient
scorpions the lateral eyes are behind the median eyes,
which are placed at the front edge of the thorax. "We
should regard therefore those scorpions in which the eyes
approximated most to this primitive position as the oldest.
Another point is the pentagonal sternum which though
lost in many adults reappears invariably in the young.
Finally the existing Buthide contain genera in which
there is a spur upon the fifth joint of the last two pairs of
limbs, a structural feature which gets its importance from
the fact that it has also been described in the Silurian
Paleophonus. Indeed it is the Buthide which show to a
CH. I] SCORPIONS OF AFRICA. 51
greater extent than any other family all these three
archaic characters. And in correspondence with this we
find them ranging widely with many peculiar genera in
different parts of the world. The different regions differ
considerably in the richness of their scorpion fauna.
Naturally—considering the tropical proclivities of the
family—the Palearctic region shows the fewest peculiar
generic types; Mr Pocock only enumerates eight; but
some of these range further into Africa than it is customary
to allow the Palearctic region to extend, the northern
limit of which is placed considerably below the tropic of
Capricorn. Africa is very rich in scorpions; unfortunately
those of Madagascar are but little known; what is known
however tends to emphasise the peculiarities of this great
island; two peculiar genera Grosphus and Tityobuthus,
belonging to the Buthide, are there to be found. In the
Ethiopian region, apart from Madagascar, there exist no
less than nine peculiar genera exclusive of the two just
mentioned besides four that get into other regions. The
Oriental region is on the whole very distinct from the
Ethiopian though naturally they have some forms in
common. Six genera are confined to the region. Of the
five that are not, three are also partly Ethiopian ; two of
those are also Australian, viz. Isometrus and Archisome-
trus; while Hormurus just gets across “ Wallace’s line.”
In the Australian region there are altogether seven genera,
of which only three are peculiar and all of these three are
limited to what Mr Pocock calls the Australian sub-region,
ie. the continent of Australia. The range of the scorpions
in fact rather supports what I have said concerning the
4—2
52 SCORPIONS OF AMERICA. [CH. I-
range of earthworms—that the Australian region should
be limited to the continent of Australia itself. It has
been mentioned that several of the genera of Old World
scorpions range into as many as three regions. We find
however no community at all between the scorpions of the
Old World and those of the New, excepting in the single
case of Cercophonius which has an Australian representa-
tive. There is too a considerable difference between the
Nearctic and the Neotropical.: Only two genera are common
to the two, viz. Centrurus and Diplocentrus. The Nearctic
which is only that portion of the Nearctic termed
Sonoran by Hart Merriam is inhabited by three other
genera. On the contrary the Neotropical region is ex-
ceedingly rich in scorpions. Mr Pocock mentions twenty-
two genera. As to families there is one, that of the
Chactide, which is absolutely confined to the Neotropical
region.
To express the distribution of the scorpions in accord-
ance with the facts it would therefore be necessary first of
all to separate the Old from the New World and then to
divide them into regions which apart from details resemble
those of Mr Sclater. The distribution of these animals
lends no assistance whatever to some of the suggested
continents that have been referred to. There is no re-
semblance between those of South America and South
Australia. And as already mentioned there are no
scorpions at all in New Zealand. But it must be borne
in mind that at present there is no information concerning
the scorpions of Patagonia, whence information of an
important character may come. There is however a close
CH. 1] LAND PLANARIANS. 53
resemblance between the South African genus Opisthocen-
trus and the Panaman Opisthacanthus, and between the
only two genera of the Diplocentride, Diplocentrus and
the Arabian Nebo. This may be merely a relic of former
warm periods prevailing in the north, of which the
existence of Tityus in amber of the Baltic is a further
indication. This genus now occurs south of the tropic of
Capricorn, thus indicating a state of climate favourable to
the migrations of scorpions by Behring’s Straits.
The Distribution of Land Planarians.
This group of worms is one that should be of great
use to the student of geographical distribution. The land
Planarians are of course of an ancient stock though
the modern representatives may be recently derived from
some one branch of this stock. They are purely terres-
trial animals, always an advantage in considering the
problems of Zoogeography; and finally it is probable,
though it is uncertain whether there are any actual
facts that can be alleged in support of the contention,
that the animals, having a coating of cilia and secreting
from their skin a slimy mucus, would be destroyed by
contact with salt water. It is however only recently that
attention has been actively directed towards the study of
this group of the Planarian worms. The late Prof.
Moseley took advantage of the opportunities afforded him
during the cruise of the “Challenger” to collect and
describe a considerable number of new forms; the litera-
ture which he gives of the subject in his paper’ shows
1 Quart. Journ. Micr. Sci. Vol. xv11.
54 RANGE OF BIPALIUM KEWENSE. [CH. I
how little had been done in the matter before his time.
Nevertheless what was accomplished by him and by Dendy,
Spencer, von Graff and the others who have succeeded
him has brought to light a good deal; we are in a position
to say something about the range of the group. The land
Planarians are as is known an artificial group; they em-
brace the terrestrial forms among the Triclad Turbellaria.
The most familiar form in the whole group is the cele-
brated Bipalium kewense, which is an absolute cosmopolite;
it has been found in many localities in England such as
Kew whence it was first obtained, the Zoological Gardens,
&c. It has turned up on the continent, in Brazil, Australia
and elsewhere; but its real home appears to be the
Fijis. With this exception, which is probably due to
artificial importation, there is no species of land Planarian
which is so widely spread, indeed no species has a great
range at all even in the country which it inhabits. Mr
Dendy has! pointed out from his study of the Australian
species that “out of twenty-nine known Australian species,
nearly equally divided between the colonies of Victoria
and New South Wales, only three have been found in both
colonies”; he goes on to remark with justice “that the
land Planarians however widely they may be distributed
as a class do not enjoy wide specific area of distribution.”
This fact of itself makes them exceedingly valuable as
examples of the importance of an invertebrate group in
contributing towards the solution of the problems of Zoo-
geography. So far as we know at present there are three
1 Trans. Roy. Soc. Vict. 1890, p. 66.
CH. I] LAND PLANARIANS OF THE EAST. 55
main groups of these worms; the Rhynchodemide, with
two eyes, the Geoplanide with many eyes and the
Bipaliide with four eyes and a hammer-shaped head.
Bipalium, with the exception of the probably accidentally
imported B. kewense, already referred to, is confined to
China, Borneo, Bengal, Ceylon and the Oriental region
generally. Geoplana is Australian, S. African, Japanese,
New Zealand, South American; and recently two species
have been described among the rich material collected by
Dr Max Weber in the Dutch East Indies. Curiously
enough that naturalist, so Dr Loman! tells us, was quite
unable to discover any land Planarians of any kind in the
island of Celebes, although he searched for them with
great care. Cotyloplana, also belonging to the same divi-
sion of the genus, is confined to Lord Howe Island, whence
it was brought by Prof. Spencer. The genus Coeloplana
of Moseley is included by recent writers in Geoplana. A
species of Geoplana was described by the late Dr Gulhiver
from the island of Rodriguez. In all probability this
genus of such wide range will bear splitting up. But in
the meantime Prof. von Graff notes that it is mainly
developed in South America. Not less than 68 of the 125
species known to Dr v. Graff are inhabitants of the conti-
nent of South America. Rhynchodemus has also a wide
range. It is met with in Europe, at the Cape of Good
Hope, in Australia, in North and South America, Ceylon,
Samoa, and the Dutch East Indies. Other genera are the
European Geodesmus, Microplana described by Vejdovsky
from dung hills, Geobia subterranea of Brazil which as its
1 Zoolog. Ergebn. Max Webers Reise.
56 LAND PLANARIANS: AN ANCIENT GROUP. [CH. I
name denotes lives under ground and subsists upon earth-
worms—as do indeed many of the species, which are for
the most part carnivorous. A species in Europe which
nourishes itself upon fungi has however been recorded.
The two genera Leimacopsis and Polycladus are recorded
from the Andes', and the former at any rate is the type
of a group distinct from any of those that have been
mentioned. Moseley described from the Philippines the
peculiar genus Dolichoplana. Now it will be observed
that the bulk of the species belonging to the Geoplanide
are South American and Australian. Only a few range
to the north of those land masses. This may be a fact of
some importance. The reader will have already made
himself acquainted with the division of the earth proposed
by Mr Huxley. The Geoplanide are almost exclusively
restricted to his Notogea; and this restriction agrees
with that of certain other ancient forms of terrestrial
anitnals such as the Marsupials. The distinctness of the
Oriental region as shown by the land Planarians is also
remarkable. It would not of course be remarkable if we
were dealing with a modern group; but the wide range of
Geoplana is so far an argument that we are dealing with a
fairly ancient group.
Altogether it seems to be evident that when the land
Planarians come to be more extensively known they will
yield a highly valuable body of facts; in the meantime
this slight sketch of their distribution may serve to il-
lustrate the impossibility of laymg down hard and fast
regional districts to apply to every group.
1 Schmarda, Neue wirbellose Thiere, 1861.
CH. 1] EARTHWORMS OF SEA SHORE. 57
The Distribution of Earthworms.
The geographical distribution of the earthworms offers
an instance of a group that is now fairly well known and
is at the same time in all probability a moderately ancient
group. It has too exceptional qualifications for careful
consideration in relation to the theories of past changes of
land in connection with the range of existing forms.
As a rule earthworms are killed by salt water; there
are exceptions such as the genus Pontodrilus which
actually lives upon the sea shore within range of at least
the splashing of the waves, and it has been asserted that
a few species in Ceylon (not named) can withstand the
action of sea water. But with these exceptions the ocean,
even when in the form of a narrow strait, is an insuperable
barrier, which is more effective than any other. As worms
have been met with at great heights upon the mountains,
there seems to be no particular difficulty in their extend-
ing their range by crossing mountain chains; probably
also rivers and large lakes are not untraversable; experi-
ments show that earthworms can be kept for some days
immersed in fresh water and yet retain their vitality, while
there are a good many instances not only of true earth-
worms (in structure) which habitually live in the water,
but there are species which live with equal ease in water
and on dry land. This is true of the European Allurus
tetredrus and of several species of Acanthodrilus. An
arid desert would doubtless prove as effectual a barrier to
migration as the sea. The only defect in this group with
58 FAMILIES OF EARTHWORMS. [CH. I
regard to the problems afforded by geographical distribu-
tion is the entire absence of any knowledge whatsoever
about extinct forms. We cannot therefore compare the
past with the present.
Earthworms are divisible into seven families :—Crypto-
drilids, Perichetide, Acanthodrilide, Eudrilide, Geo-
scolicide, Moniligastride, and Lumbricide. Of these the
first three are very nearly related and may be united into
one super-family Megascolicidz, which possibly is really
equivalent to any of the other families Eudrilide &c.
The Cryptodrilide are world-wide, but most abundant
in the Australian region and in South America. The
Perichetide are chiefly Australian and Oriental, but
occur in the Neotropical and Ethiopian regions. The
Acanthodrilide are mainly massed in New Zealand,
South America, and Africa; they are also found, though
rarely, in Australia, Malaya and North America. The
Eudrilidee are absolutely confined to Tropical Africa,
the Geoscolicidx to Tropical South America, Tropical and
Southern Africa, just reaching Kurope and Malaya. The
Lumbricide are probably only indigenous in the Nearctic
and Palearctic regions.
But it is necessary to go into further details to bring
out the salient facts in the distribution of the Oligocheta.
The list, which I shall now give, is freed from obvious
importations like the Lumbricide of exotic range dealt
with elsewhere. The same kind of argument removes
the Perichetide from the Nearctic and Palearctic
regions. Two genera belonging respectively to the Geo-
scolicide and Eudrilide, viz. Pontoscolex and Eudrilus are
CH. 1] DISTRIBUTION OF GENERA. 59
of world-wide range; but it is to be noted that the same
species exists everywhere, and that they are among the
most abundant of species in accidental or purposeful
importations of worms, thus arguing not only great
probability of their accidental introduction but showing
clearly that they can easily survive a long journey. This
is as far as I think it safe to go at present, but Michaelsen
goes further and would confine the genus Pericheta to
the Old World and the genus Benhamia to the Ethiopian
region. The genera of earthworms are thus distri-
buted :—
Palearctic. Lumbricus, Allolobophora, Allurus (L)!, Ponto-
drilus, Microscolex (C), Hormogaster (G).
Nearctic. Luwmbricus, Allolobophora, Allurus (L), Mega-
scolides, Ocnerodrilus, Microscoler (C), Diplocardia,
Benhamia (A).
Oriental. Pericheta, Megascolex, Pleionogaster, Perionyx
(P), Benhamia (A), Glyphidrilus, Annadrilus (G),
Typheus, Deodrilus (C), Moniligaster, Desmogaster
(M).
Ethiopian. All Eudrilide, Microcheta, Kynotus, Siphono-
gaster, Ilyodrilus, Bilimba, Callidrilus (G), Benhamia,
Acanthodrilus (A), Megascolex, Perionyx (P), Mill-
sonia, Ocnerodrilus, Gordiodrilus (C).
Neotropical. Rhinodrilus, Anteus, Geoscolex, Tykonus,
Urobenus, Pontoscolex, Onychocheta, Diacheta, Tricho-
cheeta (G), Microscolex, Ocnerodrilus, Gordiodrilus (C),
Acanthodrilus, Kerria (A), Pericheta (P), Monili-
gaster (M).
1 The capital letters in brackets indicate the family.
60 ANTARCTIC EARTHWORMS. (cH. I
Australian. Pericheta, Megascolex (P), Oryptodrilus,
Megascolides, Dichogaster, Microscolex (C), Acantho-
drilus, Octocheetus, Deinodrilus (A).
The above list shows how well marked the regions
are; but it loses half its significance without further
explanation. New Zealand is really very different from
Australia; it has practically only Acanthodrilide; con-
fined to it are the genera Octochetus, Plagiocheta and
Deinodrilus, and out of the eleven species of Acanthodrilus
found in the region eight are New Zealand and only three
Australian; Microscolex only just gets into Australia,
which is characterised by its Perichztide (feebly repre-
sented in New Zealand), and by the genera Cryptodrilus
and Megascolides. The Neotropical region is really
divisible into two; the southern half including the greater
part of the Argentine and Chili has only Acanthodrilus
and Microscolex, while the Geoscolicide are confined
to the tropical regions. There is thus the closest
resemblance between South America and New Zealand
which is accentuated by the fact that in intervening
localities—South Georgia, the Falklands, Marion and
Kerguelen islands—only <Acanthodrilus exists. These
evidences in favour of an antarctic continent are referred
to again later. The tropical regions of Africa and America
agree in the presence of the Geoscolicide which only just
reach Europe and the Oriental region; moreover the
African genera fall into a natural sub-family distinct from
that which contains the American forms. This fact again
has its counterpart in the Edentata among Mammals and
in some other groups.
CH. 1] RANGE OF PERICHATID. 61
The family Perichetide shows some remarkable
distributional facts. It may be divided perhaps into
five genera all of which have the complete or nearly
complete circle of sete which characterise the family ;
but they differ in other particulars. Megascolex and
Pericheta have the nephridial system arranged in what
I have termed the diffuse fashion; they are in Mr
Benham’s terminology “plectonephric.” In them there
is not a definite series of paired nephridia, but an
infinity of minute tubes which open on to the exterior by
innumerable pores in each segment. On the other hand
Diporocheta and Perionyx have the normal paired
nephridia. The genus Pericheta is also to be dis-
tinguished by the fact that very nearly all the species of
the genus have a pair of ceca arising from the intestine
at about the twenty-fifth segment. Now in Australia the
prevailing forms are Megascolex and Diporocheta. Peri-
cheta does occur, but there are not more than two or
three species. Diporocheta just gets into New Zealand.
As we pass from Australia into the Oriental region the
genus Megascolex is replaced by Pericheeta which is the
prevalent type not only of the family but of earthworms
in general in the islands of the Malay Archipelago and
the continent of India. Megascolez however lingers on,
just fading away in Madagascar.. The Oriental region is
further characterised by another genus -Perionyx which
agrees with Diporocheta in the regularly paired nephridia
but differs in the fact that the glands into which the
sperm ducts open before reaching the exterior have a
coarsely lobate arrangement instead of being coiled tubes
62 RANGE OF PERICHEATIDA, [CH. I
of equal calibre throughout. This genus just gets into
the Ethiopian region where it is represented by the
species Perionyx zanzibaricus, and possibly by another at
Durban. The true Pericheta is rare in Africa but
reappears on the opposite side of the Atlantic in Tropical
America and the West Indies. As there are a con-
siderable number of species on one side of the Atlantic
which are not found upon the other it seems likely that
the genus is indigenous in the New as in the Old
World.
It is held by some that the characteristic mark of the
Perichetide, the continuous circle of sete amounting
often to more than one hundred in a single segment, is a
primitive arrangement from which the more general eight
seta per segment can be derived by reduction; at present
however the matter is one which cannot be definitely
decided. If it prove ultimately to be the correct view, it
is noteworthy that the genus, like other ancient forms,
has a wide and discontinuous distribution, starting in the
Old World, and skipping Africa and Europe almost
entirely to reappear in the more tropical parts of America.
Moreover it is significant that in this group, as with the
mammals, Australia has the more ancient forms.
The family Geoscolicide present some interesting
facts in their distribution. The family is one of the more
modern, on the view that I take myself of the aftinities of
the group. The spermathece have lost or at any rate do
not possess the diverticula so characteristic—practically
universal—in the Megascolicide. In this they agree
with the European Lumbricide—our common earthworms
CH. 1] RANGE OF GEOSCOLICIDA. 63
in this country—in which the spermathece are oval or
roundish pouches without any czeca attached to them.
But the Geoscolicide agree with the majority of earth-
worms to differ from the Lumbricide in that the gizzard
is as it were strung upon the cesophagus, instead of lying,
as it does in Lumbricus, at the junction of esophagus and
intestine. The nephridia are always paired; but the
set differ from those of the Lumbricide in being nearly
always ornamented with raised ridges or sculpturing of
some sort; moreover there is frequently a difference
between those which occur on the segments of the
clitellum and those which are found elsewhere upon the
body. The Geoscolicide of Africa belong to the genera
Microcheta, Siphonogaster, Ilyogena and Callidrilus. I
have already referred to Kynotus of Madagascar which
is allied to these but still is different from any of them.
The family extends in the Old World into the Malay
region where it is represented by the two allied forms,
perhaps hardly generically separable, Glyphidrilus and
Annadrilus. It is represented in Europe by Hormogaster,
whose affinities are uncertain. Putting aside Stphono-
gaster, which is a remarkable and isolated type with two
extraordinary processes of the ventral body wall which may
be of the nature of penes, and Jlyogenia which may be, as
has been suggested by Dr Michaelsen, really a repre-
sentative of another family which has got to resemble the
Geoscolicidee by convergence, all these Ethiopian and
Oriental genera are alike in having a great number of
small spermathece in several segments of the body and in
having for the most part a glandulo-muscular structure at
64 EARTHWORMS OF WEST INDIES. (cH. I
the outlet of the sperm ducts and often a series of glands
which have been called for want of a better name “ copu-
latory” glands which show a structure identical with that
of the glands at the end of the male ducts. In tropical
South America and in the West Indies are the following
genera belonging to this family :—Geoscolex, Anteus, °
Rhinodrilus, Urobenus, Pontoscolex, Onychocheta, Tricho-
cheta, Diacheta, Tykonus. These genera, if they possess
spermathece, which they do as a rule, have them paired as
in the majority of earthworms. A representative of this
group Sparganophilus has been lately discovered by Dr
Benham in the Thames, and Criodrilus, usually referred
to the Lumbricide, perhaps belongs to the group, though
its position cannot be at present regarded as certain. It
is likewise European. It is a remarkable fact that
the West Indian genera present considerable differences
from the genera found on the mainland of South
America. All of them, viz. Pontoscolex, Onychocheta,
Diacheta and Trichocheta have always, or nearly always,
the sete throughout the body or of the posterior segments
arranged in an irregular fashion though there are only
the usual eight per segment. The existence of peculiar
American forms in the West Indies and of peculiar
African forms in Madagascar is paralleled in other groups
of the animal kingdom. Pontoscolex it is true also occurs
in South America; but it is so universally distributed a
form that its exact habitat is a matter of some doubt and
may as well be the West Indies as any other place. On
the hypothesis that the Geoscolicide are comparatively
speaking a modern group, their total absence from the
Sq °¢ af OL
“SNTINQOH.LNVOV ““smigang JO SAIsnioxe) Yaiivyana =
"'SAYOMHLYVS JO NOILLNEINLSIG
CH. I] ACANTHODRILIDA. 65
Australian region is a matter of moment, and recalls other
distributional facts.
Not less interesting are the distributional facts con-
cerning the Acanthodrilide. This family is divisible
into the following genera:—Acanthodrilus, Benhamia,
Octochetus, Diplocardia, Deinodrilus, Kerria and Plagio-
cheta. The family itself is separable from all other
earthworms by the fact that, with the single exception
of the species Acanthodrilus monocystis, formerly placed
by me in a distinct genus Neodrilus, there are two pairs
of spermiducal glands, which have not, as they have in
nearly all other earthworms, a near connection with the
sperm ducts, but open actually on to different segments
from them; these segments are XVII. and XIX. the
sperm ducts reaching the exterior by a pore situated
upon segment XVIII. The two pairs of glands as well as
their position are the distinguishing features of the family.
The further division of the family into genera is in some
respects not an altogether easy task. Deinodrilus is to be
at once distinguished by the fact that it has the unique
character of having twelve sete in each segment of the
body; Plagiocheta has a larger number still, as in the
Perichetide ; but the genus could not be confounded with
a Perichetid by reason of the fact that these sete are
disposed in pairs. Benhamia, Acanthodrilus and Octo-
chetus are with more difficulty separable; Benhamia and
Octochetus have the excretory organs on the same plan
as those of the majority of the Perichxtide; they are
extremely numerous in each segment of the body and
open on to the exterior by very numerous pores on each
B. Z, 5
66 EARTHWORMS OF NEW ZEALAND. [cH. I
segment. Acanthodrilus has the usual paired series of
nephridia. Kerria is a genus which is absolutely re-
stricted to America; it is noteworthy on account of the
fact that it shows in several particulars evidence of
degeneration. Thus there is only a single pair of cal-
ciferous glands in the ninth segment, a character which
it shares with several of the more simplified genera of
Cryptodrilidz, such as Gordiodrilus; the tubular glands
which open in common with the sperm duct are lined by
a single layer of cells instead of the thick layers so closely
resembling those of the clitellum which are found in the
majority of the remaining genera of earthworms.
The three genera Octochetus, Deinodrilus and Plagio-
cheta are absolutely limited in range to New Zealand,
which may be considered to be the head-quarters of the
family, as it also possesses a fair share of the known
species of Acanthodrilus. Only three species of the latter
genus are found in Australia, and it is a noteworthy fact
that these three exist in Queensland and the neighbourhood
of Torres’ Straits, on the side in fact which is turned towards
New Zealand and which has been probably at one time,
no doubt remote, joined to New Zealand. The remaining
species of Acanthodrilus are with a very few exceptions
inhabitants of the more southern regions of the South
American continent. They abound in Patagonia; but
they do not, on the east side of that continent, get
further north than Montevideo; on the other hand in
Chili the genus extends considerably further north. The
exceptions that have just been referred to relate to
Kerguelen, Marion Island, the Cape of Good Hope, and
CH. 1] ETHIOPIAN EARTHWORMS. 67
New Caledonia; in all of these countries there is one
species apiece of Acanthodrilus. This genus is unusual
though not unique among earthworms by reason of the
fact that it is largely aquatic in habit though mainly
terrestrial; even the same species, as for example Acan-
thodrilus georgianus, may be at once aquatic and terrestrial.
This naturally adds to their facility for dispersal. The
genus Benhamia is almost entirely African, that is to say
“Ethiopian,” in range; it is true that one species,
Benhamia bolavi, has been met with in Europe; but there
can be hardly any doubt that this species has been
accidentally imported ; there are also two or three species
in Mexico and the East Indies; Dr Michaelsen thinks that
these owe their presence in the countries mentioned to
the ‘effects of commerce and not to their own unaided
exertions. Finally in North America there is the singular
and somewhat aberrant genus Diplocardia, which consists
of but a single species.
The most remarkable case of a restricted distribution
among the Oligocheta is the family Eudrilide, which with
the single exception of the genus Hudrilus is not to be
met with outside of the Ethiopian region. As this genus
Eudrilus is one of the commonest forms in gatherings of
earthworms from several parts of the world, and as the
species found outside Africa do not differ specifically, I am
disposed to regard Africa as the proper home of this genus
also, and to look upon the exotic specimens as having been
accidentally carried thither. So far as our present know-
ledge goes, there are no forms outside of Africa which show
any particular resemblance to the Eudrilide. This family
5—2
68 RANGE OF CRYPTODRILIDA, [cH. I
is marked out from all others by the fact that the ovaries
are nearly always contained in special sacs, which are
developed at the expense of the septa, and whose cavities
therefore are true body cavities; and that these sacs
communicate with the exterior by the oviducts or by
special orifices or by both. In several genera the neph-
ridia, which are, as in the Lumbricide, paired structures,
a pair to each segment of the body, branch copiously in
the thickness of the body wall, opening on to the exterior
by many pores in a single segment. There are other
peculiarities of structure which mark out the Eudrilide
as one of the most isolated of families and therefore the
Ethiopian region as, from the point of view of its earthworm
inhabitants, one of the most peculiar of regions. It is
noteworthy, seeing that recently many of the West African
animals—for example the Chimpanzees—have been shown
to extend into East Africa, that the genera of earthworms
belonging to this family are not common to both sides of
the continent. We have on the west coast the genera
Heliodrilus, Hypriodrilus and Lybiodrilus among others ;
on the east coast Stuhlmannia, Polytoreutus, Eudriloides
and Notykus, &c. &c.
. The family Cryptodrilide is as has been already re-
marked nearly cosmopolitan. But the various genera of
which the family is made up are none of them of so wide
a range. Most of the principal regions have their peculiar
genera ; but the South American forms range also into New
Zealand. These species belong to the genus Microscolex
which occupies pretty nearly the whole of the South
American continent and the warmer parts of the Nearctic
CH. I] MICROSCOLEX AND OTHER GENERA. 69
region. There are altogether some nineteen species of the
genus of which those that are not American are from New
Zealand ; two species are Algerian, and they are closely
allied to two American forms that have been met with in
Australia, in Italy, and in the island of Teneriffe. This
unusually wide range of the species in question seems to be
possibly another case of accidental importation by man. In
North America there are a few species assigned by Dr
Benham and Dr Eisen to the two genera Plutellus and
Argilophilus which I cannot differentiate from the purely
Australian genus Megascolides, a genus which contains one
of the largest earthworms at present known—the giant
earthworm of Gippsland—a creature which grows toa length
of six feet. In addition to this genus, which just gets into
New Zealand with a single species, Australia has limited
to itself the genera Cryptodrilus, Digaster and Trinephrus ;
the latter genus I have thought it advisable to separate
from Cryptodrilus on account of the extraordinary fact
that its members have in each segment of the body three
pairs of nephridia. The division of the genera of Australian
Cryptodrilide is however a matter of the greatest difficulty.
In any case it appears to be clear that with the exceptions
mentioned these genera do not extend beyond the Austra-
lian region and- hardly beyond Australia itself. The
Oriental region is also fairly well off in worms belonging
to this family which are referable to the genera Deodrilus,
Typheus, Microdrilus. Africa has several peculiar forms,
including Millsonia, Gordiodrilus and two species which
Michaelsen has referred to my Fijian genus Dichogaster,
but which may be really members of a different genus; at
70 MARINE EARTHWORMS. [CH. I
present our knowledge of their anatomy is not sufficient
to decide the point definitely. In America besides the
genus Microscolex already described we have the bulk of
the species of the semi-aquatic genus Ocnerodrilus, also
found in Tropical Africa, and a species or two of the genus
Pontodrilus, which is like no other earthworms except the
ubiquitous genus Pontoscolex in living among the debris of
sea-weed on the sea-shore. The other species of this genus
live respectively in the Aru Islands, on the shores of the
Mediterranean, and the North Sea, affording an example
of the frequently wide range of forms whose habitat is a
narrow area. This family of earthworms is one that is so
difficult to classify in a satisfactory manner that it is not
wise to draw any conclusions from its range except to
point out the similarity between South America and New
Zealand.
CHAPTER II.
ZOOLOGICAL GEOGRAPHY.
In the preceding chapter a few of the more salient
facts in the distribution of animals have been detailed.
We can define an animal by its geographical position as
much as by its structure. It follows that the converse is
equally true; each country has its own special inhabitants.
One tract of country can be defined by its fauna and flora
and thus distinguished from another tract of country.
A passage across the Straits of Dover lands us in a
country which would seem at first sight to agree absolutely
with our own in its animal inhabitants; a prolonged
residence would however reveal the existence of a few
species of animals not met with in Great Britain; but
the general facies of the fauna would withstand the most
prolonged scrutiny with a view to detecting differences.
We may journey across the entire continent of Europe
without leaving a fauna generally like that which we have
at home; even the traveller in Japan will at once recog-
nize many animals which are either the same or very
closely allied to those with which he is familiar at home.
72 ZOOLOGICAL REGIONS. [cH. II
But there are greater differences between Great Britain
and Japan than between France and Great Britain.
In fact the more remote the tracts of country are
from each other, the more diverse are their faunas. But
there is no accurate balancing of distance and diversity of
fauna possible; a journey into Central Africa, shorter by
hundreds of miles than that to Japan, will bring the.
traveller into contact with forms of life altogether
different from those which occur in these islands. The
elephant, the giraffe, and the anthropoid apes will testify
to the change which has taken place in a journey com-
paratively so short. In the Eastern Archipelago are two
islands only separated by a few miles, Bali and Lombok ;
traversing this narrow strait will produce an entire change
in the fauna, greater even than that which is experienced
by the traveller from Europe to Tropical Africa. An
entirely new race of mammals will be met with, the
marsupials; while the apes, carnivora, and ungulate .
animals of the western parts of the Indian Archipelago
entirely vanish or get exceedingly rare.
Mr Sclater’s regions.
The first real attempt to divide the earth into regions
corresponding with the range of its inhabitants is that of
Mr Sclater‘.
His results were btained entirely from a consideration ~’
of the Passerine and some of the Picarian birds. Never-
theless the regions thus formed were found applicable to
1 Journ. Linn. Soc., 1857.
CH. 1] REGIONS OF MR SCLATER. 73
other groups and they have been for the most part
accepted. Mr Wallace more than anyone else has written
much in their support.
It has however been insisted upon by many that these
regions do not fit in with the facts of distribution of other
groups. That their applicability to the Passerines and to
those groups which they do suit is due to the fact that
these groups are modern and that there has in all proba-
bility not been much change in the relative distribution
of land and sea since the groups in question came into
existence. These regions however are more particularly
unsuitable to older groups, which retain, so to speak, the
impression of earlier conditions of land and sea. So much
so that the agreement or non-agreement of a particular
group with the regions instituted by Mr Sclater are in
some degree a test of its antiquity. Even in the more
modern groups the resemblance is not always striking.
Nor could we really expect that it would be; for a close
resemblance would imply a similar place of origin, an
identical series of migrations and backward migrations,
and a susceptibility to precisely the same barriers and
hindrances; these assumptions are evidently not to be
thought of as well founded. So complicated are the
conditions which govern the restrictions to migration and
the facilitation of migration that it would be impossible
to conceive of there being in any one case close corre-
spondence with another case. While therefore we cannot
expect to find a series of cut and dried regions which shall
express the known facts of distribution of all terrestrial
groups, it is of some use to have a convenient system
74 DISTRIBUTION OF MAMMALS. (cH. II
whereby the facts of distribution may be at once and with
ease appreciated.
Mr Sclater founded his regions mainly upon the dis-
tribution of Passerine birds; but in a subsequent lecture?
upon the geographical distribution of the Mammalia he
applied the same regions for the purposes of tabulating
the distribution of that group of animals also. In
considering the distribution of the existing Mammalia
four salient facts are at once apparent.
(1) Australia has both Monotremes and Marsupials.
(2) America has Marsupials but no Monotremes.
(3) The remainder of the world has Monodelphian
Mammals only.
(4) New Zealand has no Mammals at all.
On this basis Mr Sclater divided the world as follows:
I. Land where Monodelphs only occur ; no Marsupials
or Monotremes, Europe, Asia, Africa, Asiatic islands
down to Wallace’s line, North America’, This land may
be called Arctogwa.
II. Land where Monodelphs and Marsupials occur;
no Monotremes. America south of the Isthmus of
Tehuantepec. This land may be called Dendrogea,
III. Land where Marsupials prevail; no Monodelphs
but rodents and bats; Monotremes. Australia. This
may be called Antarctogea.
IV. Land without Mammals (except bats)* New
1 «The Geographical Distribution of Mammals.” Science Lectures
for the People, 1874.
2 The common Opossum ranges however into this region.
3 For a possible exception see below.
‘4
CH. II] MR HUXLEY’S REGIONS. 75
Zealand and the Pacific islands. This land may be called
Ornithogea.
Arctogea is then subdivided into the well known
Palearctic, Ethiopian, Indian and Nearctic regions. But
it is pointed out that these sections are not equal to the
remaining and undivided Antarctogea and Dendrogea.
The fourth section, Ornithogea, is necessarily left out of
consideration altogether, as it contains no Mammals (with
a trifling exception or two). A better name for this
division of the earth’s surface is perhaps that suggested
by Prof. Lankester, viz. Atheriogzea, since it expresses the
cardinal fact in its zoogeography : which is not the posses-
sion of a rich bird fauna but the absence of an indigenous
Mammal fauna.
Mr Huxley’s regions.
A study of the distribution of the Alectoromorpha led
Prof. Huxley to suggest a different division of the world
into regions.
The Peristeropodes (the Cracide and Megapodidz) are
confined to a range of country which includes continental
Australia and some of the islands to the north, along with
South and Central America; this tract of the earth’s
surface he termed Notogea, the part lying to the north
being called Arctogea. Arctogea is tenanted by the
following families of birds which are at most but poorly
represented to the south of the line already mentioned :—
the Pteroclide, Otidie, Gruide, Vulturide, Upupide and
Bucerotide. This area is almost coincident with the
range of the Insectivora, and it is the head-quarters of the
76 NOTOGHZA AND ARCTOGA. [cH, 11
Ungulata. Ganoid fishes are not found outside it. On
the other hand the southern region has all the Ratitz
(except Struthio), the Tinamous, the American Vultures
(Cathartide), the bulk of the Pigeons and the Parrots
including the most peculiar forms of both, and nearly all
the Trochilide and Aptenodytide. Such remarkable and
isolated types of birds as the Palamedeide, Psophiide,
Cariamide and Opisthocomide are also confined to it.
Among Mammals it is characterised by the Marsupialia,
the Platyrrhine monkeys, the Monotremata, and most of
the Edentata. It is poor in Ungulata.
This region of Notogea is again divided by Prof.
Huxley into three divisions, which he names Austro-
Columbia, Australia and New Zealand.
The most obvious criticism to apply to these, and
which has been applied, is that they are quite out of
proportion ; this is particularly the case with New Zealand,
which has so few types of great importance as compared
with Austro-Columbia. I do not however enter into any
detailed criticism since the actual way in which the earth
is divided up is so largely a matter of convenience—as is
admitted on all hands.
Other suggested regions.
Some have wished to make a separate region of Mada-
gascar, which has unquestionably a large number of
peculiar types. Arctic and Antarctic regions commend
themselves to many.
Quite the most unsatisfactory region, in my opinion,
CH. 11} POLYNESIAN REGION. 17
that has been proposed is the Polynesian adopted by Prof.
Heilprin’. This is meant to include the scattered islands
to the east of Australia, comprised between lat. 20 N.
and lat. 408. Prof. Heilprin admits that this region is
defined “more by negative than by positive characters,” a
necessary admission, though not convincing of the justice
of framing it. He distinguishes it by the absence of all
Mammalia except a few bats, Pteropide and Vespertilio-
nide. The birds include no special families excepting
only the Rhinochetide and the Didunculide and Drepani-
dide. All the other families are either exclusively
Australian types or are birds of a wider range, including
Australia. Among lizards the most remarkable form is
the Iguanid Brachylophus from the Fijis. The same
islands harbour three species belonging to the frog genus
Cornufer and a toad, Bufo dialophus. If he includes,
which appears probable though there is no definite
statement upon the point, the Solomon Islands in this
group, we can add to his list as distinctive of the “region”
the huge Rana guppyt, a species of the Marsupial genus
Cuscus, besides a crocodile, several snakes, and some more
lizards and Amphibia. There is no remarkable assemblage
of peculiar genera such as differentiate the other regions;
the differences that do characterise this so-called region
are merely due to the isolation of the different islands
which are either (as in the case of the Solomon Islands
according to Blanford) remnants of former land connection
with Australia or New Guinea, or oceanic islands which
have been populated from the nearest mainland, ie.
1 Called Nesogwa by Prof. Gill, Proc. Biol. Soc. Washington, Vol. x.
78 HOLARCTIC REGION. (cH. I
Australia. That there should be peculiar genera is quite
in accord with both these modes of origin; but the fewness
of the peculiar genera and their alliance with Australian
forms seems to render it necessary to place the entire
Polynesian realm within the Australian, and.at most to
regard it with Mr Wallace as a subregion (exclusive in
this case of the Solomons).
Mr Sclater’s regions the most convenient.
The question is, What system shall we adopt ?
The ideal system would be one which agreed entirely
with the distribution of land and sea and their inhabitants;
but that is unfortunately impracticable. The next best
is obviously the plan to try; and Mr Sclater’s regions are,
with an exception here and there, coincident with the
continents and larger islands. The great thing is not to
dispute the standard to be taken, but to agree in holding
to one standard. As a mere matter of convenience it is
immaterial whether we join Europe, Asia, and North
America into one Holarctic region, or use the current
terms of Nearctic and Palearctic for the Old and New
World divisions of this extensive tract. What we want
to do is to find a common outline into which the details
can be inserted. Mr Wallace in a recent lecture upon
the regions most convenient for adoption’ urges the
retention of the Sclaterian regions for the following three
principal reasons :—
(1) They are founded upon and approximate to the
great primary divisions of the earth, which there is reason
1 Nature, 1894.
CH. II] REASONS FOR ADOPTING MR SCLATER’S REGIONS. 79
to believe have been permanent during considerable
geological periods.
(2) They are rich and varied in all the main types of
life. ‘
(3) They possess great individuality; whether ex-
hibited by the possession of numerous peculiar species,
genera, or families, or by the entire absence of genera or
families which are abundant and wide-spread in some of
the adjacent regions.
Mr Wallace admits that these regions are not quite
perfect in all of these requirements, but they are more so
than any other arrangement which has been devised. The
Nearctic for instance is the poorest and the Neotropical
region is the richest; there is not an absolute equality
between any two; nor could the world be split up so as to
attain to that desirable end. It is a matter of the very
smallest importance to wrangle over the division which is
most natural; as Mr Wallace says “there is no question
of who is right and who is wrong in the naming and
grouping of these regions or of determining what are the
true primary regions. All proposed regions are from
some points of view natural but the whole question of
their grouping and nomenclature is one of convenience
and utility in relation to the object aimed at.”
It is clear that if our Zoological regions were to be
constituted on the evidence afforded by the groups of
animals whose range has been briefly sketched in its
main outlines on previous pages they would not agree
entirely with those of Mr Sclater or with each other.
The Herpetological regions show a marked difference
80 DIFFERENT DIVISIONS OF EARTH'S SURFACE. [CH. II
in the first place between the Old and New Worlds: Asia
and Australia are nearer together than either of them is
to Africa; and Africa is more nearly akin to Europe than
_ to any other region. New Zealand forms a region quite
apart from the others.
The earthworms on the other hand do not show so
marked a distinction between the Old and the New
Worlds; indeed they offer the best evidence of any group
in favour of the Holarctic region. The Ethiopian region
is very distinct, perhaps the most distinct of all. The
Australian region is barely separable from the Oriental.
It is quite necessary, in order to emphasise the facts
of distribution in this group, to constitute an Antarctic
region embracing New Zealand and Patagonia.
The Batrachians are again quite different from either
of the other two groups considered. The Neotropical and
the Australian really form one big region; so also do the
Ethiopian and the Oriental; on the other hand the
Nearctic and the Palearctic are quite distinct; there can
be no question here of a Holarctic realm.
To express in a graphic form the distribution of the
land Planarians is a simpler matter than in the case of
any of the other groups.
The following pages contain schemes of the distribu-
tion of some of these groups which are compared with the
Insecta whose range in space and peculiarities of distribu-
tion I have not treated of at all. The diagrams of most of
these are taken from M. Trouessart’s book already referred
to more than once and they represent the latest and most
reliable information from specialists on the several groups.
Cl CH. 1] PLANS OF DISTRIBUTION. 81
REPTILES
Nearctic Europe Asia
Africa a |
Australia
and
Neotropical Polynesia
Ca
EARTHWORMS
Holarctic
Neotropical Ethiopia Oriental
Australia
¢ Antarctic b
BATRACHIA
Nearctic
j
Ethiop.| Oriental
Neotropical
ao Australia
1 @ Madagascar, b New Zealand, c Patagonia.
B, Z.
82 USE OF BIRDS FOR DEFINING REGIONS. [CH. II
COLEOPTERA
Holarctic
4
Indo-
Brazil E Polynesia African
5,
°
2
Patagonia Australia
Le fo
Upon what group then shall we found our divisions of
the earth’s surface ?
The great objection to the birds is that they can
fly and are therefore independent of most barriers; with
them temperature, food and pre-occupation of the ground
must be the chief limitations to universal range. More-
over it will be remembered that this group contains the.
largest number of cosmopolitan genera and species. All
this tends to throw the claims of the birds into the
background. Against their exclusive use also is the fact
that they are a modern race, and would therefore at best
only indicate the present arrangement of land and sea,
At the furthest the birds go back to the Jurassic period ;
while the Carinate birds (speaking zoologically and not
etymologically) are not of greater age than the Tertiary
period. All curves of development show that birds are now
in the ascendant and that they have risen rapidly into
prominence. To this is due the variance of opinions
CH. 11] MOLLUSCA AND ZOOLOGICAL REGIONS, 83
that prevail with regard to their proper classification.
So intimately connected are the various types that it is
difficult to define the groups; and all classification has to
go upon that most unsatisfactory plan, the averaging of a
number of structural characters. A thinning out of the
numberless existing genera might reveal the main lines
of ascent just as the branches of a tree stand out more
plainly when they are denuded of the leaves. I have
attempted to show elsewhere (p. 81, 82) that it is difficult to
get any real justification for the generally adopted regions
by the study of the range of different families. All that
can be said in most cases is that the various regions have
each a certain number of peculiar genera and families;
but those facts lose value from the impossibility of
making definite statements about the mutual affinities
of the genera in question. The Gallinaceous birds which ©
are less endowed with power of wing than many other
groups offer the best evidence of a connection between
structure and distribution. So too the Struthious birds,
Land Mollusca would appear on many grounds to be
exceedingly valuable as furnishing evidence in favour
of ancient land connections.
In an interesting paper Prof. Kobelt, a great authority
upon the group, urges their claims to be put in the fore-
front of animals useful for this purpose.
There is however more than one serious objection
to their use. As Mr Blanford points out, we are not
at present in a very forward state of knowledge as to
what conchologists term “the animal”; the anatomy
of the group is for a large part ignored by those even who
6—2
84 CHARACTERS OF MOLLUSCA. (cH. Ir
make the group their special study. The relationships
therefore of the different genera is in many cases obscure.
They can therefore not be made use of in a strictly
scientific comparison of the faunas of various parts of the
world. We know how varied may be the structure of
other animals—even belonging to the same group—under
a superficial similarity; for example the genus Doriopsis
among the Nudibranchs differs from the genus Doris
(sensu lato) by the total absence of that most character-
istic molluscan organ the odontophore; and yet with this
important dissimilarity it would be impossible to separate
the two genera by any marked external characters.
Were one totally unacquainted with their internal
structure the Brachiopods and Lamellibranchs might be,
as they have been in the past, associated closely together.
Analogous differences may separate some of the genera
of Pulmonata whose anatomy is not known.
In the second place they are very capable in some
way or other of crossing the ocean, for we find them in
oceanic islands which cannot have been stocked inde-
pendently with them. Mr Wallace remarks that “they
have no means of passing over the sea but such as are
very rare and exceptional.” He quotes however Darwin’s
experiment to the effect that a Roman snail lived after
immersion in salt water for twenty days. For further
examples of the ways in which the terrestrial Mollusca
can cross the sea the reader is referred to a later
chapter.
If it were not for these objections the land Mollusca
would be a most important group; they are extremely
CH. II] MAMMALS AND ZOOLOGICAL REGIONS. 85
ancient, the existing genera Pupa and Zonites going back
to Carboniferous times.
Mr Wallace urges the superior claims of Mammals
upon whose distribution to found Zoological regions. He
thinks that they are best qualified “to exhibit by their
existing distribution the past changes and present physical
condition of the earth’s surface.”
The reasons for this opinion are according to Mr
Wallace the following:—{1) They are dependent for
their means of dispersal upon continuity of land. At
least wide seas would be impassable. (2) They are (with
the exception of the bats which fly and might therefore be
subject to gales, and the mouse tribe which might be—are
in fact—conveyed in ships) too large to be carried acci-
dentally across seas which they could not traverse by
their own unaided efforts. (3) Again they are so highly
organised as to be largely independent of other animals;
though both purely carnivorous and purely vegetarian
forms exist there.is for the most part no dependence
upon any particular kind of animal or plant as food, such
as we meet with for example among the insects. Or
where there is a restriction in the matter of diet as in the
case of the anteaters both of the old and new worlds the
food is universally found. (4) The mammalia form a group
which is fairly well known anatomically, we can therefore
form a tolerably correct judgment as to their mutual
relationships. That this is the case is shown by the
absence of any differences of opinion as to the outlines
of the main subdivisions of the family. (5) The last
argument favourable to the Mammalia is the fact that
86 PAST HISTORY OF MAMMALS. [CH. IL
we have a better knowledge of extinct forms than we
have of any other existing group. It is perfectly true
that this knowledge will bear increasing and that it is
practically limited to the extinct genera of Europe and
North America with certain parts of South America and
India. But after all compared with other groups the
knowledge is undoubtedly considerable.
Though all this is perfectly true, yet the Mammalia
are by no means an ideally perfect group for these
purposes.
In the first place they are a comparatively modern
group, dating back at the furthest to the triassic period.
They are therefore perhaps to be regarded as representa-
tives of the present state of affairs in land and sea. They
have for example in all probability never reached New
Zealand, between which and New Australia there may
very likely have been an ancient land connection some-
where in the early secondary period or even earlier. The
Mammalia also, although a comparatively modern race, are
a waning race; as it has been said, we live in a world
which is as regards mammals zoologically impoverished.
This has brought about the existence (if the hibernicism
be allowed) of so many missing links. The Marsupials for
example, though called by Mr Huxley Metatheria and
believed by him and by others to stand midway between
the Monotremes and the higher Mammalia, with a more
near approximation to the latter, cannot be satisfactorily
tacked on to any particular group of the Eutheria. The
very fact that the living Mammalia can be so easily
classified, and that there is so little difference of opinion
CH. 11] BEST GROUP FOR DEFINING REGIONS. 87
about the scheme of classification, shows the breaks that
exist between the various families. Though it is true that
we have a fair anatomical knowledge of the Mammalia,
yet there are plenty of lacune; the broad facts are
perhaps ascertained, but there are many details of im-
portance which require further elucidation. For instance
there is but little knowledge, and that purely osteological,
of the structural differences between the different kinds of
bears and cats. These two families have a wide distribu-
tion and it would be of great interest to know if for
example the muscular anatomy of the new world forms
is distinctive of them and different from that of the old
world genera or species. Besides much of our knowledge
of the Mammalia is limited to skins and horns, in many
cases necessarily. Unsuspected differences so constantly
turn up between superficially very similar forms, that
further knowledge is desirable. A noteworthy instance
are the discoveries by the late Prof. Garrod in the anatomy
of the soft parts of the rhinoceroses.
On the whole, however, it is impossible to avoid agree-
ing with Mr Wallace that the Mammalia are the most
satisfactory group. And moreover the adoption of the
regions necessitated by the distribution of this group is
in harmony with the distribution of some other groups
and does no great violence to distributional fact any-
where.
88 PALZARCTIC REGION. ‘(CH. Ir
The six Zoological regions of Mr Sclater.
In the pages that follow I have purposely refrained
from a detailed account of the faunas of each; much that
is not to be found in the present section will be found
elsewhere. I have here simply abstracted from Wallace
and other books a list of the genera absolutely confined to
each region, and given a few forms which are highly
characteristic of, though not absolutely confined to, each
region.
I. The Palzarctic region.
This region contains in the first place the whole of
Europe with the outlying islands of Iceland in the north
and down to the Cape de Verde islands in the south.
The north of Africa to the tropic of Cancer is included by
Mr Wallace, though others prolong the Palearctic region
further to the south; the Arabian peninsula is divided
into two approximately equal halves by the line of division
between the Palzarctic and the Ethiopian region. The
whole of the north of Asia including Japan belongs to this
region, which reaches the Arabian sea along the coast of
Persia. The delimitations of the Oriental region are along
the southern slopes of the Himalayas, Afghanistan and
Baluchistan going with the Palearctic. In China the
limits of the Palzarctic region are at about Shanghai
on the coast.
(i) Families of animals confined to the Palearctic
region. .
None.
CH. IT] PALEARCTIC REGION. 89
(ii) Genera confined to the region.
Talpa ; Scaptochirus ; Myogale ; Scaptonyx ; ite:
rosorex (Moles).
Lutronectes (an Otter); Meles (Badger).
Camelus ; Dama (Fallow deer); Capreolus (Roe
deer); Hydropotes, Lophotragus, Elaphodus (Cer-
vide); Bos, Poephagus (Yak); Addax, Procapra
Saiga, Panthalops, Rupicapra (Antelopes);
Capra (Goat tribe).
Myoxus (Dormouse); Spalax (Rodentia).
Luscinia, Accentor, Frithacus (Sylviide); Panurus
(“ Bearded tit”); Garrulus, Perisoreus (Jays);
Nucifraga (Nutcracker); Cyanocitta, Fregilus
(Chough); Fringilla, Acanthis, Montifringilla
(Finches).
Perdia, Tetraogallus (Gallinacez).
Ibidorhynchus (Scolopacide).
The region is however also chaiacterised by a large
number of forms which have their chief development
therein, though they extend over its boundaries,
The genus Phasianus is nearly confined to the region
and other allied genera such as Thawmalea the Golden
Pheasant, Certornis the Tragopan, and the Ipeyan Phea-
sant, Lophophorus, have their greatest. development within
this region, though they do as a matter of fact cross its
border and pass into the Oriental region.
A great many of the Mammalia are either specifically
identical with North American forms or are very near
indeed to them. The Aurochs and the Wapiti are hardly
if at all specifically different from Luhdorf’s deer and the
90 PALHARCTIC AND NEARCTIC. (cH. 11
American bison. The grizzly bear, though it has received
the specific name of Ursus ferox, is barely distinguishable
from the brown bear Ursus arctos of Europe ; there is no
doubt at all about the identity of the reindeer, the elk,
the glutton and the arctic fox which are common to the
Nearctic and the Palearctic regions. The lynx, wolf,
marten, beaver and marmot are forms common to both
regions without differences at all or showing differences
of the slightest possible kind. All these animals are
among the most characteristic of those inhabiting the
Palearctic region. The pouched rats Cricetomys are, as
has been recently shown by the leading authority upon
this group, Mr Thomas, hardly generically separable from
the American Hesperomys. The musk deer, Moschus, and
the peculiar bear-like creatures Ailuropus and Ailurus are
not confined to the Palearctic region; they are as charac-
teristic of it however as they are of the Oriental region, in
which they also occur. Even the tiger so pre-eminently,
according to popular literature, a denizen of the tropics,
may be fairly counted as an inhabitant of the temperate
or even subarctic Palearctic region since it has been met
with so far north as the Amur. It is but recently that
there were similar resemblances between the fauna of the
western part of the Palearctic region with that of Africa;
the hippopotamus, the Maltese elephants, the lion and
various other creatures have only lately become extin-
guished in this continent. While the mammoth of Siberia
and elsewhere is held by some to be the actual progenitor
of the Indian elephant, which is thought by them to hardly
rank as a different species but to be rather a variety which
cH. I] PALARCTIC SUB-REGIONS. 91
has lost its hairy covering on becoming an inhabitant of a
hot climate. The hairy rhinoceros of Europe is another
case in point.
The Palearctic region is divided into (I) Huropean,
(11) Mediterranean, (III) Siberian, (IV) Muntchurian
sub-regions.
I. The Luropean sub-region comprises Central and
Northern Europe. The only really peculiar genus is the
Desman, Myogale, found in the streams of the Pyrenees
and of Southern Russia. Many other Mammalia however
are highly characteristic of the sub-region, though not
positively confined to it. Such are the wolf, the mole,
the hedgehog, and the dormouse. Not a single genus
of birds is absolutely confined to the sub-region. But the
Wagtails, the Tits and the Reedling, Panurus', are genera
which are more abundant in this part of the world than
elsewhere.
II. The Mediterranean sub-region, as might be in-
ferred from its warmer climate, is by far the richest portion
of the Palearctic region. Besides that part of Europe
bordering upon the Mediterranean Sea, it includes the
north of Africa, down to the desert of Sahara, Persia and
Baluchistan. Among Mammalia the Fallow deer (Dama)
is peculiar to the sub-region; so too are Psammomys and
Ctenodactylus, two genera of rodents. The Civet of the
south of France and South Europe generally, the Porcupine
and others are among the characteristic though not
peculiar genera. These and some others show the African
affinities of the Mediterranean sub-region. The Hyena
1 Sometimes (and inaccurately) called the ‘‘ Bearded tit.”
92 PALHARCTIC SUB-REGIONS. (cH. 1
and the Lion point to the same transitional character.
Among birds two warblers, Zusciniola and Pyrophthalma,
are peculiar.
III. The Siberian sub-region includes the whole of
Northern Asia. Of Mammals the yak and two antelopes,
Procapra and Panthalops, are confined to it; the mole
Nectogale is another peculiar form and completes the list
of genera that are found here and in none of the other
sub-regions. The musk deer however, Moschus, is nearly
confined to the sub-region, while many Arctic animals, such
as the sable, the glutton, and the reindeer are highly
characteristic of it; the two latter as already mentioned
also extending their range into the Nearctic region.
Among birds there are few peculiar forms. The only
genus that is “most decidedly” confined to the region is a.
genus of Starlings Podoces.
IV. The Mantchurian sub-region, bordering as it does
upon the tropics, is rich when compared with other parts
of the Palzarctic region. It includes all Japan besides
_Corea and other parts of China. Some of the peculiar
deer, discovered by Pére David and his associates, are
peculiar to this sub-region. Such are Hydropotes and
Elaphodus. The curious Nyctereutes and the carnivore
4Ailuropus axe also peculiar forms or nearly so, The
former is often called the “raccoon-like dog”; the latter
genus is allied to the Panda, #lurus. Both of these
occur also in the Oriental region. A genus of Otters,
Lutronectes, is also peculiar, and there are a few other
genera which are found in this sub-region and not in the
other sub-regions of the Palearctic region. The birds are
CH. 11] NEARCTIC REGION. 93
represented by an abundant variety of species; but as
many of them are common to this and to the Oriental
region which borders upon it, it is a little difficult to
disentangle the faunas of the two. Some of the mag-
nificent pheasants of the East, the genera Lophophorus,
Pucrasia, Thaumalea, and Crossoptilon, are characteristic ;
but these have already been mentioned as among the
birds characteristic of the region as a whole. There are
also species of Ceriornis and Phasianus.
II. The Nearctic region.
This region consists of the whole of North America,
together with a portion of Mexico, into which, according to
Mr Wallace’s map of the region, it sends a narrow tongue
‘along the central mountain range. As Mr Wallace has
pointed out, the greatest width of the continent in the
more arctic parts of it and its narrowness where the
climate becomes more congenial is largely responsible for
the comparative poverty of the fauna.
List of families peculiar to the Nearctic region.
Saccomyide (Pouched rats), Haploodontide (Ro-
dentia).
Chameide (Passerines).
Genera peculiar to the region.
Synotus, Autrozous (Baits).
Condylura, Scapanus, Scalops (Moles).
Lataz, Taxidea (Carnivora).
Antilocapra, Ovibus, Haplocerus (Bovide).
94 NEARCTIC REGION. [oH. 1
Neotoma, Sigmodon, Jaculus, Cynomys, Erethizon
(Rodentia).
Salpinctes, Catherpes, Gymnokitta Picicorvus, Cent-
ronyx, Neocorys, &c. (Passeres).
Ectopistes (Columbide).
Pilohela (Scolopacide).
Highly characteristic of the region, among the Mam-
malia, are in the first place the bison and the grizzly
bear; it is not quite certain, as I have already mentioned
under the description of the Palearctic region, whether
these animals are specifically distinct from what are at
the very least close allies in Europe and Asia. But if so
the bison, now limited to a single herd from previously
existing thousands, is a noteworthy type of American life,
no less than is the formidable “grizzly.” Bassaris, an
animal now known to be allied to the Raccoons, but
formerly placed in a different division of the Carnivora, is
one of the numerous forms that are so common to the
Nearctic and Neotropical regions, but has a larger range
in the former. The Puma and the Skunks are other
examples of animals which extend northwards from the
South American continent. Among birds, humming birds
and various members of the families Mniotiltide, Vireo-
nide and Cerebide are examples of Neotropical forms
which also extend into the North American continent.
The same is the case with the Tanagers and several
South American genera of Fringillide. The black cuckoo
with a deep bill, the ani, Crotophaga, is also met with in
North America, though more characteristic of South
America.
CH. If] NEARCTIC REGION. 95
A closer resemblance between the Nearctic and the
Palearctic regions than that which obtains between, say
the Neotropical and the Ethiopian, would be expected on
the theory of the polar origin of life. That there is a
close resemblance has also some relation to the great
similarity in climate and physical conditions between the
two regions. But the question now for consideration
is whether the similarity is such as to warrant the
inclusion of the two in one Holarctic realm, as is
contended by Dr Heilprin and Prof. Newton. Dr Wallace
decidedly thinks not; and his reasons for this opposition
are set forth in a special paper devoted to the question.
It appears from his tables that there are 43 genera of
Mammals which are found in the Palearctic region but
not in the Nearctic. On the other hand 39 are peculiar
to the Nearctic; 31 are common to both regions.
These estimates, even when slightly edited, as will be
indicated immediately, leave a respectable balance of
forms peculiar to each region; doubtless the number of
forms is poor when compared with other regions; but it
must be borne in mind that these two temperate regions
do not abound in Mammalian life as do the more tropical
parts of the earth’s surface. Of the 39 genera peculiar
to the Nearctic region seven may be not unfairly deducted
in making a final estimate as being largely, if not to a
greater extent, Central or South American, ie. Neo-
tropical, also. The peccary, for example, is an animal
which is rather characteristic of the Neotropical than the
Nearctic region. The most striking argument however
1 Natural Science, June, 1894.
96 NEARCTIC SUB-REGIONS, (CH. 11
for the reunion of the regions is afforded by the con-
sideration that out of the 31 genera that they have in
common it is only possible -to withdraw three, as being
aquatic and therefore having a range of less significance,
and four which are exclusively or largely Arctic. Removing
in addition four genera of ubiquitous bats there are left
16 genera which are common to the two regions. This
calculation is made on the basis of genera admitted by
Mr Wallace; on a more liberal estimate of what is meant
by a genus the number of genera would of course be
increased.
The Nearctic region is usually divided into the four
following sub-regions: (I) Californian, (II) Rocky Mountain,
(IIT) Alleghany, (IV) Canadian.
I. Californian sub-region. This includes besides Cali-
fornia a considerable part of British Columbia. It has
several peculiar genera of Mammals. Among them are
Enhydra a sea otter, Urotrichus a mole and Neosorex a
shrew. Haploodon, a rat-like rodent, is peculiar to this
sub-region, as are also the only North American repre-
sentatives of the bat families Phyllostomide and Nocti-
lionide. The birds also embrace some peculiar forms.
The “road runner” Geococcy# and the aberrant Passerine
Chamea, which Dr Shufeldt places near to the Tits, are
found here and nowhere else in the region. There are
other characteristic birds, but few that are absolutely
confined to the sub-region.
II. Central or Rocky Mountain sub-region. The “big-
horn” sheep (Ovis montana), the Antilocapra and the goat
Haploceros are among the most characteristic Ungulates
CH. 11] CANADIAN SUB-REGION. 97
confined to the sub-region. The bison so reduced in
numbers now-a-days is almost confined to the Rocky
Mountain sub-region. The prairie dog, Cynomys, a close
ally of the marmot, is restricted to the sub-region. Birds
contribute their quota toward distinguishing the sub-region
from those which border upon it. But they are genera
and not families. Among them may be mentioned the
following: Salpinctes, a wren, Poospiza, a finch, and Pe-
diocetes, a grouse.
III. astern or Alleghany sub-region. Mr Wallace
remarks that this sub-region “contains examples of all
that is most characteristic of Nearctic zoology.” But
there is only one genus of Mammalia that is absolutely
confined to it. This is Condylura, the star-nosed mole.
Only 30 birds are mentioned by Wallace as peculiar to
the region among non-migrants.
IV. The Subarctic or Canadian sub-region. This
naturally presents many features of resemblance to the
arctic parts of the Palearctic region. It is charac-
terised for example by such forms as the glutton, reindeer
and elk, which pass into the Palearctic region also.
The musk deer however, Ovibos, is limited to this region,
having apparently been a few times found outside of it in
the Palearctic region. The birds though numerous are
not so peculiar: it upsets the current notions as to the
tropical habits of the humming-birds to learn that a
species, Selasphorus rufus, breeds in Alaska.
98 ETHIOPIAN REGION. [cH. II
III. The Ethiopian region.
The Ethiopian region consists of all Tropical and
South Africa, from about the Tropic of Capricorn (see
Palwarctic region); it also includes the island of Mada-
gascar and the adjacent Mascarene islands.
(i) Families peculiar to the Ethiopian region.
Chiromyide (Lemur).
Potamogalide, Chrysochloride (Insectivora).
Cryptoproctide, Protelide (Carnivora).
Hippopotamide, Camelopardalide (Ungulata).
Orycteropodide: (Edentata).
Buphagide, Philepittide (Passeres).
Musophagide, Coliide, Leptosomide, Irrisoride
(Picarians). .
Serpentarvidee (Accipitres).
Struthionide.
(ii) Genera peculiar to the region.
Gorilla, Anthropopithecus, Colobus, Cercopithecus,
Cercocebus, Cynocephalus (Primates).
Indris, Lemur, Galago, Chirogaleus, Hapalemur,
Lepilemur, Perodicticus, Arctocebus, Micro-
cebus (Lemurs).
Epomophorus, Hypsignathus, Macronycteris
(Bats).
Petrodromus, Rhynchocyon, Centetes, Hemicen-
tetes, Ericulus, Oryzoryctes, Echinops (Insecti-
vora).
Helogale, Bdeogale, Eupleres, Cynictis, Lycaon,
Megalotis, Ictonyx, &c. (Carnivora).
CH. II] PECULIAR AFRICAN ANIMALS. 99
Potamocherus, Phacocherus, Oreas, Kobus, Al-
cephalus, &c. (Ungulata).
Lasiomys, Lophiomys, Saccostomus, Pedetes, Ano-
malurus, Aulacodus, Pectinator, Bathyerges,
Georychus, &c. (Rodents).
Parisoma, Artamia, Hypocolius, Corvultur, Hy-
phantornis, Vidua, Buphaga, Crithagra, Ama-
dina, &c. (Passeres).
Dendropicus, Geocolaptes, Pogonorhynchus, Buc-
canodon, Xylobucco, Coua, Atelornis, Ispidina,
Bucorvus, Toccus, &c. (Picarians).
Alectrenas, Gina, Chalcopelia, &c. (Columbide).
Agelastes, Numida, Ptilopachus, &c. (Gallina-
cee).
Polyboroides, Lophoaétus, Melieirax, Nisoides, &c.
(Accipitres).
Mesites, Himantornis (Rallide).
Scopus, Baleeniceps (Ardeide).
The lion, panther, elephant, and rhinoceros are also of
course among the most characteristic African Mammalia.
Of Rhinoceroses there are apparently three species, of
which only two, R. stmus and R. bicornis, are at all known.
The third has been lately reported. Also limited to this
region are the zebras and quaggas, the last practically,
if not actually, extinct. Of chimpanzees there are two
well-marked species, the “common” chimpanzee and
Anthropopithecus calvus, a species discovered by du
Chaillu and until lately represented by a living specimen
(“Sally”) at the Zoological Society’s gardens. It is
quite likely that these are not the only two species’ of
7—2
100 MAMMALS AND BIRDS OF AFRICA. [cH. Ir
chimpanzee. The Ethiopian region contains the majority
of the antelopes; but in contrast to this abundance of
antelopes is the total absence of deer. Another group
which might be expected to occur, but which is in-
explicably absent, is that of the bears. - The hippopotamus
is represented by two species, one of which, the small
Liberian hippopotamus, has been placed in a distinct
genus, Cheropotamus. This proceeding however according
to Sir William Flower is unnecessary. The Lemurs,
which form so characteristic a part of the fauna of this
region, are nearly all of them limited to Madagascar—as
indeed are many of the peculiar Ethiopian genera. They
have been treated of in the more particular account which
I give elsewhere (below) of the fauna of Madagascar. One
or two resemblances between Africa and the Neotropical
region have been noted under the account of the latter.
Most of the resemblances of Africa are with the Oriental
region. Thus the hornbills and barbets range through
both regions, as do the panther and lion. The elephant
and rhinoceros are only found in the Oriental region
outside of the Ethiopian; but the species, and even,
according to some systematists, the genera are different
in the two cases.
Among birds, the huge whale-bill (Balwniceps) is one of
the most remarkable of African types. Its ally, the hammer-
head (Scopus), which seems to stand half-way between
the Herons and Storks, is a widely-spread African type.
The ground hornbill, which is undoubtedly a hornbill,.
though a very aberrant one, is almost equally singular.
The colies and plantain eaters (Coliide and Musophagide).
CH. II] SUBDIVISIONS OF ETHIOPIAN REGION. 101
are two groups of uncertain affinities; as the late Prof.
Garrod pointed out, the latter has resemblances to the
Gallinaceze. Mesites of Madagascar will be found referred
to under the description of the fauna of that island. The
peculiar types of birds are by no means so numerous or so
important as they are in South America.
The Ethiopian region is divisible into the fillowiag
sub-regions: (I) Hast-African, (II) West-African, (III)
South-African, (IV) Mascarene.
East-African sub-region. This sub-region includes
not only east but also the greater part of central Africa,
and it extends to the north so far as to include Arabia,
Abyssinia and the south of Egypt. Below the Sahara it
extends right across the continent to the Atlantic, its
lower boundary being at about the river Gambia, and
again below the West-African sub-region it extends right
across. Among the peculiar Mammalia of this sub-region
are the Gelada baboon of Abyssinia, the curious little
naked and burrowing rodent Heterocephalus and another
rodent, Pectinator. The rhinoceroses and the giraffe are
practically confined to it, but this restriction is one of the
many cases of the limitation of faunas largely due to man.
Among birds the boatbill Baleniceps is peculiar, and so is
the shrike Hypocolius. But on the whole the sub-region
is not well marked by its peculiar types, though abound-
ing in the characteristically African forms.
II. The West-African sub-region extends as far south
as the Congo. It is characterised by the Gorilla and by
at least one species of Chimpanzee, the Anthropopithecus
caluus. The Potto, Perodicticus, and the nearly allied, if
102 ORIENTAL REGION. [cH, 11
not generically identical, Angwantibo (Arctocebus), are the
lemurs which are confined to this sub-region. Potamogale,
an Insectivore with the appearance and the habits of an
otter, and Hyomoschus complete the list of the more
salient mammalian types which are West-African. Among
birds perhaps the most remarkable form is a species of
Pitta, the only species of this oriental genus which reaches
Africa at all. The birds are on the whole not remarkable
or distinctive.
III. The South-African sub-region is bounded to the
north entirely by the East-African region, which here as
well as to the north of the West-African sub-region
extends right across the continent. The sub-region has
one family to itself, the Chrysochloride or Golden moles.
The Hyznoid genus Proteles and the Hunting dog Lycaon
are peculiar to it. Bathyerges and the jumping hare
Pedetes are among the eighteen genera of. mammals
which are peculiar to South Africa. The birds are not
remarkable.
IV. The Mascarene sub-region is dealt with below.
IV. The Oriental region.
To this region Mr Sclater at first gave the name of
“Indian”; but Mr Wallace proposed to replace this name
by the more general expression “oriental,” a suggestion
which has met with Mr Sclater’s approval. This region
comprises not only the peninsula of India and the more
tropical parts of China, but it includes also a large pro-
portion of the islands of the eastern archipelago. The
CH, II] PECULIAR GENERA OF ORIENTAL REGION. 103
boundary between it and the Australian region has been
termed “ Wallace’s line,” and divides the island of Bali
from that of Lombok to the south, and the island of
Borneo from Celebes on the north.
(i) Families peculiar to the Oriental region.
Galeopithecidee, Tuwpatide (Insectivora).
Phyllornithide, Eurylemide (Passerines).
(ii) Genera peculiar to the region.
Simia, Hylobates, Siamanga, Presbytes (Primates).
Nycticebus, Loris (Lemurs).
Megerops, Aquias, Phyllotis, &c. (Bats).
Gymnura (Insectivora).
Vwverricula, Arctogale, Cyon, Arctonyx, Mydaus,
&c. (Carnivora).
Tragulus, Cervulus, Portax, Antilope, Tetraceros
(Ungulates).
Platacanthomys, Spalacomys, Phloeomys, Pteromys,
Acanthion (Rodents).
Garrulax, Timalia, Mixornis, Paradoxornis, Eni-
curus, Salporms, Dendrophila, Sylviparus, Cissa,
Urocissa, Dendrocitta, &c., (Passeres).
Chrysocolaptes, Megalema, Phenicophaés, Carpo-
coccyx, Nyctiornis, Harpactes, Buceros, <Aceros,
- Rhinoplax, &c. (Picarians).
Pavo, Polyplectron, Euplocamus, Galloperdix (Gal-
linacez),
Hierax, Ketupa, Photodilus (Accipitres).
Hydrophasianus (Rallide).
Among the most characteristic animals of this region
104 ORANG AND GIBBON. [cH. II
stands in the first place the Orang, of which there may or
may not be more than a single species. The Anthropoid
apes are also represented by the agile family of the Gibbons
(Stamanga and Hylobates). The two genera of Apes,
Macacus and Cynopithecus, might really for all practical
purposes have been included among the list of peculiar
genera, for they only just get outside the region. Among
carnivorous animals the Tiger is one of the most noticeable,
though it is not strictly confined to the region, getting
north into even the colder parts of the Palearctic region.
The remarkable lemur Tarsius, which is generally made
the type and only member of a special family of the
Lemurs, only just ranges beyond the Oriental region,
while the “Slow Loris” and an ally represent the more
normal lemurs. The Ungulates are many and character-
istic. In addition to the peculiar genera mentioned in the
above list there is of course the Indian elephant and the
Malayan Tapir; three out of the five existing species of
rhinoceros are also natives of this region. The others, as
has been already mentioned, are Ethiopian; the porcupine
Atherura is a genus which is common to this region and
to the Ethiopian. So too the Manis or Scaly anteater.
The flying squirrels, Pteromys, get as far north as Japan,
but there are some who would place at least the southern
portion of this empire in the Oriental rather than in the
Palearctic region. Of birds the family Timeliide, the
“ Babbling thrushes,” are very nearly absolutely confined
to this region; in Mr Wallace’s list 21 out of a total of 27
genera, which he allows to the family, are exclusively
Oriental. Some of the most magnificent species of the
CH. 11] ORIENTAL SUB-REGIONS. 105
pheasant tribe are entirely or mainly restricted to this
region and are among the most characteristic of the bird
inhabitants. The Cuckoos are well developed, and are
represented by 18 genera, of which 2 are peculiar to the
region; but here, as in so many: cases, the limits of the
genera are somewhat uncertain. The Bee-eater Nyctiornis
is an oriental genus, and oriental only. The parrots are
abundant, but there is only a single peculiar genus,
Psittinus. The rest are mainly of Australian types, but
the genus Palwornis is in addition African. The remark-
able owl Photodilus has perhaps a near ally in Heliodilus
of Madagascar, both of these genera, especially the latter,
are again allied to Striz and form with it a special sub-
family of the Owls. Another highly characteristic genus
of birds is the Surgeon bird, Hydrophasianus, which has
an ally in the genus Parra in the New World. The
Ralline birds are however not abundant or represented by
many peculiar types in the Oriental region.
The Oriental region has also four sub-regions, (I)
Indian, (11) Ceylonese, (IIT) Indo-Chinese, (IV) Malayan.
I. Indian sub-region. This sub-region comprises the
entire peninsula of Hindostan. It does not abound in
peculiar forms, but there are a few which are confined to
it. The genus Teniogale among the Viverride is in this
position; the majority of the oriental Antelopes have
here their head-quarters.
II. The Ceylonese sub-region includes besides the island
of Ceylon a large part of southern India. It is a little
richer in peculiar types, but is still not very peculiar.
The lemur Loris is found here; the rodent genus Plata-
106 FAUNA OF. CELEBES. [CH. 11
canthomys is another peculiar type. Several species of
“ Holy ape” (Semnopithecus) are limited to this sub-region.
As to the birds Mr Holdsworth allowed in. 1872, 325
species, of which-37 are peculiar to Ceylon. This number
is raised by Mr Wallace to 80 for the whole sub-region.
There is only one genus that is peculiar, viz. Hlaphrorms
and a sub-genus Sturnornis.
III. The Jndo-Chinese sub-region includes the Hima-
layas as well as Siam and tropical China. Among peculiar
genera of Mammals are the Viverrines Urva and Arctonyz,
and the remarkable carnivore d#lurus'. There are a
number of peculiar birds of the passerine and picarian
groups; these include the genera Liothrix, Urocissa, Aceros
(a hornbill), and a number of others; the Gallinaceous
Ceriornis (the Tragopan) is another genus nearly limited
to the sub-region.
IV. The Malayan sub-region, as might be inferred
from the fact that it is almost entirely made up of islands,
has a number of peculiar forms. The Anthropoid apes of
the east are most abundant here, and the Orang is found
nowhere else: the lemur Tarsius is very nearly confined
to this sub-region, not occurring in any of the other sub-
regions but just passing the boundary of the Australian
region. The insectivore Gymnura, the curious mountain
living carnivore Mydaus, the Indian Tapir are among
other mammals that are confined to this sub-region. If
we regard the island of Celebes*, that “fragment of
miocene Asia,” as a part of this region—a position to
' 1 This is also palzarctic.
2 Mr Sclater does in his most recently expressed opinion, Ibis, Oct. 1891.
CH, 1] NEOTROPICAL REGION. 107
which Mr Wallace does not commit: himself—it is a tower
of strength in the way of peculiar forms. There are here
the Babirussa, the Bull-antelope (Anoa) and the ape
genus or sub-genus Cynopithecus. Among birds this sub-
region has as peculiar to it the genus Timelia among the
“Babbling thrushes,” Hupetes,a curious form which Mr
Forbes placed in the Timeliide, and quite a number of
other Passerine genera. The Australian Megapodius gets
into this sub-region, and there is the cuckoo Carpococcys.
V. The Neotropical region:
This region has obvious boundaries for the greater
part of its extent, since it consists of the continent of
South America. It also includes the West Indies and
the greater part of Central America.
(i) Families peculiar to the Neotropical region.
Cebide, Hapalide (Quadrumana).
Chinchillide, Caviide (Rodents).
Bradypodide, Dasypodide, Myrmecophagide (Eden-
tates).
Cerebide, Oxyrhamphide, Pipride, Cotingide, Phy-
totomide, Dendrocolaptide, Formicariide, Ptero-
ptochide (Passeres).
Rhymphastide, Bucconide, Galbulide, Todide, Mo-
motide, Steatornithide (Picarians).
Cracide, Tinamide (Gallinacez).
Opisthocomide (“ Hoatzin ”).
Thinocoride, Cariamide, Aramide, Psophiide,
Eurypygide, Palamedeide (“Gralle”).
108 BIRDS OF 8S. AMERICA. [cH. I
(ii) Genera peculiar to the region.
Pteronotus, Chilonycteris, Noctilio (Bats).
Solenodon (Insectivore).
Icticyon, Galictis, Nasua, Cercoleptes (Carnivora).
Dicotyles, Lama (Ungulates).
Neotomys, Cercolabes, Chetomys (Rodents).
Chironectes, Hyracodon (Marsupials).
Mimocychla, Donacobius, Cyanocorax, Basileuterus,
Sycalis, Diuca, &c. &c. (Passeres).
Picumnus, Chloronerpes, Guira, Neomorphus, Pany-
ptila, &c. &c. (Picariz).
Ara, Caica, Chrysotis, Pionus, &c. (Psittaci).
Columbula, Zenaida, Starneenas, &c. (Columb).
Odontophorus, Dendrortyx, Eupsychortye (Galli-
nace).
Sarcorhamphus, Spiziastur, Morphnus, &c. (Acci-
pitres).
Heliornis, Oreophilus, Pluvianellus, &c. (Rails).
Tigrisoma, Cancroma (Ardeide).
Micropterus, Merganetta (Anatide).
Rhea (Struthiones).
Besides the peculiar families enumerated above the
Nearctic region shares with the present the exclusive
possession of the Humming-birds (Trochilide), Tanagers,
Mniotilitide, Vireonide, Tyrannide, Conuride, of all of
which the bulk of the species are South American. The
American vultures, which have been aptly termed by Mr
Seebohm Mimogypes, are chiefly neotropical, but also
range into the northern hemisphere. Of characteristic
CH. 11] PECULIAR TYPES OF ANIMALS. 109
forms not by any means either as to the family or the
genus to which they belong, which are confined to this
region, extending sometimes for a greater or less distance
into the Nearctic, are the Tapirs, which are represented
by several species, some of which were separated by the late
Mr Alston as a distinct genus Elasmognathus: the Jaguar
and the Puma among the Carnivora, the former being
confined to the region: the Opossums of the genus
Didelphys are found here and in the southern parts of
the Nearctic: the Skunk may be mentioned in the same
category as the last: Bassaris is a carnivorous animal
whose affinities, now known to be with the bear tribe,
were at one time unrecognised; it also extends into the
warmer parts of North America. The number of peculiar
genera belonging to the region is very large. Four of the
peculiar Gralline families contain but a single genus
apiece and very few species between them; they are all
of them birds whose position in the system is much
disputed, owing no doubt to their being the impoverished
relics of groups of birds at one time more abundant.
Palamedea and Chauna are believed to be a relic of an
ancestral tribe of anatiform birds; Cariama is said by
some to present resemblances to the Secretary bird of
Africa and to have therefore some relations to the birds
of prey. Psophia and Aramus are more distinctly rails,
while Hurypyga again is a bird which is allied to the
New Caledonian Rhinochetus, and to the Madagascar
Mesites, and possibly represents the sole remaining Ame-
rican type of a nearly extinct order of birds once
universally distributed. Of Opisthocomus the same kind
110 TINAMOUS AND CURASSOWS. [cH. II
of remarks can in all probability be safely made. It
seems to be an outlier of the Gallinaceous tribe, which is
itself represented in this region by two other ancient
families (see p. 28), the Tinamide and the Cracidz, of
which of course the Tinamide are the most ancient,
inasmuch as they alone of all Carinate birds resemble the
Ostrich tribe in the absence of any fusion between the
pubes and the ischia. The Oil-bird (Steatornis) cannot
perhaps lay claim to any great antiquity but it is a very
remarkable type of Caprimulgine bird. The Trogons and
Barbets are also found in the Ethiopian and Oriental
regions. The scarlet Ibis, and the Boatbill Cancroma—a
Night Heron with an enlarged beak, approaching that of
the African Baleniceps—are other instances of peculiar
South-American birds.
The Neotropical region is divisible into four sub-
regions; these are (I) Chilian, (II) Brazilian, (III)
Mexican, (IV) West-Indian.
I. The Chilian sub-region. This includes the whole
of Patagonia and the greater part of Chili; the Andes
divide it to the north from the Brazilian sub-region. It is
well marked by several groups of animals, which give it
a perfectly distinctive character. In the first place we
have the rodent family of the Chinchillide; the Llama,
Huanaco, Alpaca and Vicuiia belonging to the genus Lama,
are as characteristic ; two genera of Armadillos, Tolypeutes -
and Chlamydophorus, are restricted in their range to this
region, and it has other peculiar rodents in addition to
the family mentioned. Among birds the family Thino-
coride with the two genera Thinocoris and Attagis, which
CH. IT] TAPIRS AND EDENTATES, 111
the late Prof. Garrod showed to be most nearly related to
the “Courser” of the old world, is one of the most typical
of the sub-region. The Tinamou genus Calodromas, with
cxca unique in their complicated branching, is also
confined to the sub-region. Rhea is equally limited to
this part of the world, and there are numerous other
genera of birds belonging to many families, which exist
only in the Chilian sub-region. Among earthworms it
contains all or nearly all of the genera Acanthodrilus and
Microscolex; this group of animals offering one of the
best reasons for its separation.
II. The Brazilian sub-region. This sub-region includes
all the forest region of South America and is practically
coextensive with the political division of the continent
known as Brazil. It reaches up to the sea on the north
and across the Andes on the west. The monkeys, Lago-
thrix, Brachyurus and Pithecia, are limited to this region,
which indeed contains nearly all of the arboreal animals of
South America. The Tapirs of the genus Tapirus are
found here only. The Great Anteater (Myrmecophaga),
the Sloth Bradypus and a few Armadillos are confined to
the sub-region. Among birds it has the isolated genera
Psophia and Eurypyga, besides innumerable genera be-
longing to the Cotingidz and other families.
III. The Mexican sub-region. This sub-region is in
some respects intermediate between the rest of the Neo-
tropical and the Nearctic regions. It is not so rich in
peculiar types of South American animals as are either of
the sub-regions already described. There are however not
a few types entirely restricted to tropical Mexico. Among
112 WEST INDIES. (CH. 11
the most important of these is the mountain Tapir
Elasmognathus; the Bassaris, a raccoon-like animal for-
merly and wrongly assigned to the Viverride, is Nearctic
as well as central American. The only other genus of
Mammalia which is really confined to the sub-region
besides the Tapir is a genus of mice, Myzomys. As with
the Mammalia so with the birds this sub-region is the
common meeting ground of the Nearctic and Neotropical
fauna, with a distinct bent towards the latter. Mr
Wallace states that there are in all 37 genera of land
birds confined to it, all of which are of common Nearctic
or Neotropical families,
IV. The West-Indian sub-region. This sub-region
consists of the islands of the West Indies, and bears a
somewhat analogous relation to the continent of South
America that the island of Madagascar does to that of
Africa. As far as concerns Mammals it is largely marked
by negative characters; there are no Edentates, monkeys
or Carnivora; but the two older (?) groups of mammals,
Rodents and Insectivora, are represented by peculiar types.
The latter is represented by the genus Solenodon, which
belongs to the family Centetide, elsewhere only found in
Madagascar. The Rodent Capromys is the most peculiar
representative of its order. The birds are also remarkable ;
the genus Todus, which the late Mr Forbes elevated to a
group equivalent to the rest of the Picarian birds, is
found here and here only. It is widely spread in the
islands and has peculiar forms in many of them. The
other birds are not so remarkable; they are characteris-
tically neotropical, belonging to such families as Trochilid
CH, If] “ WALLACE’S LINE.” 113
(Humming birds), Cotingidz (Chatterers), Ccrebide
. (Sugar birds).
VI. The Australian region.
The Australian region consists, as its name denotes, of
the Australian island-continent; it also embraces the
island of New Zealand to the east and various small
scattered islands in the neighbourhood of this. The
islands of the Pacific lying to the north and to the east of
Australia also are referable to the same region, as are the
great islands of New Guinea, and probably Celebes. The
chain of East Indies beginning with Java is partly
Oriental and partly Australian ; the division between the
two often spoken of as “ Wallace’s line” lies between the
islands of Bali and Lombok.
One order, the Monotremata, is peculiar to this region.
Families peculiar to the Australian region.
Dasyuride, Myrmecobiide, Peramelide, Macropo-
didee, Phalangistide, Phascolomyide(Marsupials).
Paradiseide, Meliphagide, Drepanididee, Menuride,
Atrichiide (Passeres).
Platycercide, Trichoglosside, Nestoride, Stringopide
(Parrots). 7
Didunculide (Pigeons).
Rhinochetidee (Gralle).
Casuariide, Apterygiide (Struthiones).
Genera peculiar to the region.
Hypoderma, Notopteris, Mystacina (Bats).
Babyrussa (Pigs).
Anoa (Bovide).
B, Z, 8
114 AUSTRALIAN BIRDS. (cH. II
Pseudomys, Hapalotis, Hydromys, Acanthomys,
Echiothriz (Rodents).
Malurus, Calamanthus, Orthonyx, Artamides, Pachy-
cephala, &c. (Passeres).
Scythrops, Rhamphococcyx (Cuckoos).
Dacelo, Tanysiptera, Podargus, Aegotheles, &c.
(Picarians).
Calopsitta, Microglossus, Hos, Eclectus, Trichoglossus,
&c. (Parrots).
Turacena, Calenas, Otidiphaps, Phaps, Geophaps,
&c. (Pigeons).
Talegallus, Megacephalon, Lipoa (Megapodes).
Urospiza, Uroaétus, Harpa, Hieracidea, &c. (Accipi-
tres).
Ocydromus, Tribonyx, Habroptila, Pareudiastes
(Rallide).
Thinornis, Pedionomus, Anarhynchus, Erythrogonys
(Charadriidz).
Malacorhynchus, Hymenolemus, Biziwra, Cereopsis
(Anatide)’.
The family of the Megapodes is as nearly as possible
confined to this region, a single species getting as far as the
Andamans in the Oriental region; so too the Cacatuide
which extend beyond it only to the Philippines. Of
course the most impressive character of the region is the
possession of nearly all the Marsupials; with the excep-
tion of a single family, the Didelphide, found in North,
1 The above list contains the peculiar Celebes genera. The relations
of this island are extremely doubtful.
CH. 11] PARROTS AND PIGEONS. 115
Central and South America, there are no Marsupials found
outside of Australia and the Australian region. As this
region consists so largely of islands it might be expected
that the peculiar forms have often an extremely limited
range within it; that is the case, and I have dealt
elsewhere with the fauna of New Zealand, which is an
important part of the Australian region, so important
indeed that it has been proposed to separate it off as an
equivalent region. Among the characteristic animals of
Australia that do not belong to genera or families limited
to the region is the wild. dog, the Dingo; it has been
doubted whether this is really an indigenous animal at
all.
It is often suggested, or perhaps left to be inferred,
that the Avifauna of this region is inferior in its distinc-
tiveness to the Mammalian; no-doubt the absolutely
unrivalled peculiarity of that fauna tends to obscure by
contrast the real and numerous peculiarities of the bird
fauna; but a glance at the above list will show that
Australia and its adjacent islands in reality abounds with
peculiar types of birds. It is specially noteworthy on
account of the great abundance and variety of the Parrots,
being comparable to—indeed really excelling in this
respect—South America. Highly characteristic also of
the region are the Pigeons. These rather defenceless
birds, which have no beak or claw to speak of, and which
construct rude and easily accessible nests exposed to view
in the most open manner, possibly owe their abundance
to the absence of a great variety of Carnivorous Mam-
malia, They are also to a considerable extent marked
8—2
116 AUSTRALIAN SUB-REGIONS. [CH. II
with green, a protective colour in the forests which they
inhabit. Mr Wallace, to whom the above suggestions in
explanation of the great prevalence of Pigeons are due,
estimates that “three-fourths of the genera have repre-
sentatives in the Australian region, while two-fifths of
the whole are confined to it.”
The Australian region is not quite so destitute of
Mammals not belonging to the orders Monotremata and
Marsupialia as is sometimes apt to be inferred. Apart
from the peculiar genera of Rodents and the few other
peculiar forms enumerated in the above table, a Macaque
and a Cynopithecus get into the region where it touches
the Oriental; the remarkable Oriental Lemur the Tarsius
also enters the region; Viverride and shrews are not
unknown, though few and rare; the genus Sus extends as
far into the region as New Guinea. On the whole this
is perhaps the most isolated in its affinities of all the
regions. The boundary between it and the Oriental is
sharply marked; I have dealt elsewhere (see below) with
such resemblances as it affords to other parts of the world
and the Neotropical region.
The Australian has four well marked sub-regions, viz.,
(1) Austro-Malayan, (II) Polynesian, (III) Australian, and
(IV) Novo-Zealanian.
I. The Papuan or Austro-Malayan sub-region in-
cludes not only New Guinea and all the islands lying to
the west of it as far as the commencement of the Oriental
region, but the extreme north of the continent of Aus-
tralia. Being entirely, or nearly entirely, made up of
islands it has a large number of peculiar forms.. The
CH. 11] MARSUPIALS. 117
Marsupials get to thin out here considerably; but there
are peculiar genera; in New Guinea itself we have
Dorcopsis ; the Tree Kangaroo Dendrolagus is confined to
New Guinea and North Queensland; a genus of Pha-
langers Distechurus is also peculiar, and there are several
species characteristic of these islands; the recently dis-
covered Echidna, Proechidna bruijnii, is peculiar to New
Guinea. Among birds the most characteristic are the
Birds of Paradise belonging to the genera Paradisea,
Manucodia, Seleucides and many others. The cockatoo
Microglossus is a peculiar genus and the Cassowaries have
here their headquarters.
II. Polynesian. This sub-region is largely dealt
with below; it is characterised rather by the absence of
forms which ought, so to speak, to be there than by the
presence of peculiar forms.
III. The Australian sub-region is of course the head-
quarters of the Marsupials and Monotremes, of which
latter group the Platypus is restricted to the sub-region.
Among Marsupials the Wombats, Thylacine and Koala
are confined to it. Another remarkable type of Marsupial
entirely confined to this sub-region is the small insect-
eating Myrmecobius; the lately discovered “ Marsupial
mole” is another type which marks out this from the
other sub-regions. This sub-region has according to Mr
Wallace a larger proportion of peculiar birds than any
other sub-region of any region. Nineteen-twentieths of
the birds are confined to it. The Emeu and the Cereopsis
goose are among the most characteristic forms.
118 COLOUR AND DISTRIBUTION. [CH. II
IV. The Novo-Zealanian sub-region comprising New
Zealand and some of the adjacent islands is described
in detail below.
Some graphic Methods of presenting the facts
of Distribution.
In order to get a clear idea of the facts of Zoogeography
and to compare one series of facts with another it is
requisite to present them in a graphic fashion. The usual
method is to indicate the different Distributional regions
upon a map by the help of varied colour. The colour
might even be made to some extent appropriate; the
Neotropical region—Dendrogeza as Mr Sclater terms it—
preeminently a region of forests and inhabited by so many
arboreal types, might be conveniently coloured green;
those who accept the Holarctic realm of Prof. Newton
might suitably leave it white in order to suggest the
characteristic Arctic forms. Prof. Camerano has recently
attempted to show that there is a distinct relation between
colour and geographical range. He thinks that yellow is
the prevailing colour in Africa, grey in Asia and so forth.
This method of colouring the primary regions may com-
mend itself to some. A difficulty is offered by the
transitional tracts which combine the characters of the
two regions between which they lie. These transitional
areas are perhaps more marked between the Palearctic
and the Ethiopian on the one hand and between the
Palearctic and Oriental on the other. Prof. Mobius?
colours these transitional areas with a paler hue of the
1 Die Tiergebiete der Erde &c. Archiv f. Naturg. 1891, p. 277.
CH. I] DIAGRAMS OF DISTRIBUTION. 119
tint applied to the region which they most resemble,
Dr Heilprin prefers to shade the transitional areas. This
method however is too voluminous and expensive to be
used in illustration of the geographical range of different
species, genera and families. The number of maps re-
quired is reduced by a plan adopted by Dr Grevé’ in a
series of papers upon the distribution of the different
groups of Carnivora. The areas of certain species that do
not overlap are coloured with different tints; where there
is an overlapping the boundaries are indicated by differ-
ently coloured lines made up of dots or strokes or crosses
&c., &c. The complexity of the result thus produced
seems however to counterbalance the econorfiy of space.
There is no doubt that maps convey a more rapid and
accurate impression than tables; and Mr J. A. Allen has
eliminated the element of expense by suggesting diagram-
matic maps which can be constructed of lines and dashes
in ordinary use by printers. The following scheme
Nearctic Palearctic
i :
Ethiopian Oriental
i 8
Neotropical
¢ Australian
1 Zoologische Jahrb. Abt. f. Syst. Bd. v1. 1892.
120 . REPTILES AND (cH. II
slightly altered from the original, indicates the regions
of Sclater and Wallace with the principal sub-regions,
Le. (a) Madagascar, (b) Malaya, (c) Patagonia, (d) New
Zealand.
The wavy lines connecting certain of the regions show
that they are related. This method (which I have
already utilised) is useful for indicating the range of
species, genera or families, the names of which can be
written in the spaces; but it is more particularly
advantageous for a broad survey of the divisions of
the earth’s surface which a study of different groups
necessitates and which may be compared. The following
are Trouesgart’s schemes of herpetological and mammalian
regions.
REPTILES
Palearttic
Nearctic
Oriental
Ethiopian
a
Australian
Neotropical
d
CH. I1] MAMMALS, 121
MAMMALS
“Aretic
Holarctic
Ethiopian - Oriental
Neotropical ;
Australian
d
Antarctic
Mr Mitchell has recently* devised a still further sim-
plification which again can be printed from ordinary type
lines. The regions may be thus indicated.
Nearctic Palearctic
Neotropical Ethiopian Oriental
Australian
The scheme may be made more complete by the
1 P.Z.S. 1890, p. 607.
122 MR MITCHELL'S SCHEME. [cH. 11
addition of the sub-regions. As Mr Mitchell points out
the four sub-regions of each region except in the case of
the Nearctic lie in a general way two to the north and
two to the south. The sub-regions may be indicated by
the following numbers.
Palearctic region. Ethiopian region.
N. European 1 W. African 1
Mediterranean 2 8. African 2
Siberian 3 EB. African 3
Manchurian 4 Madagascar 4
Oriental region. Australian region.
Hindostan 1 Austro-Malay 1
Ceylon 2 Australia 2
Indo-China 3 Polynesia 3
Indo-Malay 4 New Zealand 4
Nearctic region. Neotropical region.
Canada 1 Mexico 1
California 2 Chili 2
Rockies 3 Antilles 3
E. States 4 Brazil 4
The complete scheme therefore will be as follows with
the sub-regions shown.
me 09
boo
m 09
CH. 11] DIAGRAM OF RANGE OF LEMURS. 123
The range of any particular form is given by leaving
out all but the sub-regions where it occurs, putting these
in their proper place. Thus the range of the existing
Lemurs would be expressed in the following way.
oo
wo
m oO
It might be advantageous to mark in heavy type those
sub-regions which are especially inhabited by the animal
in question, and various other modifications are of course
possible and will suggest themselves. The great advan-
tage of Mr Mitchell’s scheme is that it can be so easily
used for the purposes of blackboard demonstration in
lectures.
CHAPTER III.
THE CAUSES WHICH INFLUENCE THE DISTRIBUTION
OF ANIMALS.
Distribution not dependent upon temperature.
It was at one time held that distribution depended
upon temperature; that therefore the world could be
divided into zones corresponding to the belts of varying
temperature.
That the range of animals is to a large degree depen-
dent upon temperature is an undoubted fact; and to a
certain extent that fact does permit of the zonal arrange-
ment of the earth. Only however as concerns the arctic
regions; here we have occasionally the same species
ranging right round the pole as we have in the case of
the marine mammalia and the birds of the south pole.
Some even go so far as to unite for the same reason the
Palearctic and Nearctic regions. On a priori grounds
too there would seem to be something to be said for a
series of circumpolar regions; as the earth cooled life
would be able to advance from the poles towards the
equator, and the whole matter has recently been resusci-
tated in the polar theory of the origin of faunas (see
below).
CH. Tit] RANGE OF ARCTURUS. 125
Distribution of Crustacean Arcturus as illustrative
of connection between range and temperature.
It is chiefly marine organisms which show a close
interdependence of temperature and distribution. The
Isopod genus Arcturus and the nearly related Astacilla
prevail chiefly in the antarctic hemisphere; it is only
recently however that they have been obtained from that
part of the world. Until the voyages of the German ship
“Gazelle” and the English vessel “Challenger” the two
genera were only known from the northern hemisphere.
Four or five species of Astacilla occur on the coasts of
Great Britain, N. America and Northern Europe; while
the large Arcturus baffini is the only representative of its
genus from the north, which is an inhabitant of shallow
seas. It is in the antarctic region of the globe that
Arcturus is so prevalent. Two species named Arcturus
coppingert. and A. americanus occur in the shallow water
off the coasts of Patagonia; three species of Arcturus, viz.
A. furcatus, A. studeri, A. stebbingi, are met with on the
shores of Kerguelen, besides a peculiar genus still refer-
able to the same family and containing one species
Arcturides cornutus. A single Astacilla, A. marionensis
lives, as its specific name implies, on the shores of Marion
Island, not so far from Kerguelen; finally there is a
peculiar form with eyes on long but immobile stalks,
Arcturus oculatus, on the shores of South Australia. In
addition to these inhabitants of shallow water there
are a number of species which are only found in deep
water and one (Arcturus furcatus) which lives in both
126 SHALLOW WATER AND DEEP SEA ARCTURUS. [CH. III
shallow and deep water—a very rare exception so far as
this group is concerned. The purely deep sea forms with
their habitats are the following :—
. glacialis, Antarctic.
. spinosus, Antarctic.
. anna, Antarctic.
. brunneus, Antarctic.
. myops, Antarctic.
. cornutus, Indian Archipelago.
. spinifrons, Fiji.
. purpureus, West Indies.
. abyssicola, Society Islands and Cape York.
. tuberosus, Arctic.
. hystria, Arctic.
ea a a a
The facts at our disposal about the distribution of this
family appear to indicate that the genus Arcturus is
typically a deep sea genus; there are twelve deep sea
species as against seven shallow water forms, one being
common ‘to both coasts and sea of great depth. The
shallow water forms are with one exception exclusively
antarctic in range; while in the closely allied genus
Astacilla the converse is the case, there being but one
antarctic species. The facts look very much as if range
here were more a question of temperature than anything
else; the intervening hotter parts of the oceans are
without Arcturt; but the southern forms have been able
to reach the northern hemisphere or vice versa by taking
a long dive and coming up again above the equator. The
deep sea in fact is a cool pathway along which Crustaceans
CH. II] FLORA OF NEW ZEALAND. 127
unable to withstand the higher temperature of the surface
waters in the tropics can pass in safety.
This view however may be too elaborate; besides it
should apply also to the Serolide which are considered
below’; another suggestion may arise from the habits
of these Crustaceans; the Serolidz live at the bottom and
swim and crawl on the sand; the Arcturide on the other
hand are stated to cling with their hinder thoracic limbs
to any available object; in this way they might easily
happen to select some floating piece of wood which would
ultimately take them on a voyage to the more northern
from the more southern regions.
An analogous series of facts with perhaps an analogous
explanation is offered by the flora of New Zealand. There
are many resemblances in the flora of New Zealand to
that of Europe. Mr Wallace says that “one-third of the
entire number of New Zealand genera (115) are found
also in Europe, and even fifty-eight species are identical
in these remote parts of the world.” No doubt it is easier
for many plants than for many animals to cross wide
tracts of ocean, but Mr Wallace is of opinion that mountain
ranges offer a convenient mode of transit which has been
probably made use of. The difficulties of a change of
temperature would be in this way overcome; as a matter
of fact European plants are known from intermediately
lying mountain tracts such as the Himalayas.
1 In the Chapter dealing with the Antarctic continent.
128 SPARROW IN UNITED STATES, [cH. 101
The country inhabited by an animal is not neces-
sarily the only one in which it can flourish.
The view that animals are suited to the countries
which they inhabit and to no others, that in fact their
distribution is a matter of temperature, is proved to be
quite untenable by the phenomena of colonisation. Sir
Charles Lyell’ refers to the case of the Ligurian bee, Apis
mellifica, which is a native of Europe. It was however
introduced by the early settlers into America and has
since that time prospered exceedingly on its own account,
apart altogether from the protection afforded by man to
his own hives. It inhabits the forests of the interior and
builds its combs in hollow trees.
The most striking instance however of successful in-
vasion of a new country by foreign colonists is offered by
the sparrow. This bird is now as ubiquitous in most
parts of the United States as it is in this country. To
such an extent has it proved capable of adapting itself to
a new soil and somewhat different climate that measures
concerted for its destruction by the United States Govern-
ment have proved quite incapable of producing any great
effect upon its numbers; and yet it is only a few years
since it was artificially introduced.
Perhaps the most striking example among plants of
the capacity which an introduced organism sometimes
possesses of suiting itself to new circumstances is the
common canal and pond weed of this country, the Anacharis,
1 Principles of Geology.
CH. II] INTRODUCED ANIMALS. 129
which was introduced some years since as a rare and
interesting botanical specimen.
The rabbits in Australia are another example, whose
abundance in a country which might appear from the
nature of its fauna to be unsuitable to the higher Mam-
malia, has so far baffled the attempts of science to lessen
their numbers. Within the last few years also a species of
Zosterops has naturalised itself in New Zealand, this being
a case of colonisation not helped or caused by man. The
Bee-fly, Volucella, has also of late taken up its abode in
the same country and in other parts of the world.
In fact plenty of examples might be cited from various
groups of the animal kingdom to show that there is by no
means always a close and inviolable connection between
a given animal and the habitat in which it happens to
flourish.
Similarities in the faunas of distant countries.
Dr Seitz has lately complained that a perusal of such
books as Mr Wallace’s work upon distribution give an
erroneous impression of the characters of different countries.
He read that South America has an infinite number of
Cotingide and Pipride, both of which families of birds
are confined to it; but during his visit to that continent
he only occasionally heard the Cotingide, the Bell-bird
Chasmorhynchus to wit. On the other hand he was
struck by the resemblance of tropical Africa to tropical
America in the large beetles called by the specific names
of “Hercules” and “Goliath.” The brightly coloured
B. Z. 9
130 FAUNAS OF TROPICAL COUNTRIES. {cH. III
flying moths of the tropics of the old and the new worlds,
the Agaristide and Castniide, the toucans of America
and the hornbills of the East also contribute to giving
them a similarity. So too the apes and monkeys; while
the newts of the colder regions distinguish them from the
tropics. The humming-birds of America have a superficial
likeness to the sunbirds of the old world; the tapir occurs
in tropical America and recurs in tropical Asia. Plenty
of other such resemblances might be cited.
But a closer examination of the facts dispels the ideas
of a similarity of the fauna to which they at first give
rise. The humming-birds are not nearly related to the
sunbirds; nor are the toucans the nearest allies of the
hornbills; ornithologists think that the latter come next
to the hoopoes. The apparent similarity in fact is due
to a variety of causes.’ The deserts of America are
tenanted by sandy-coloured reptiles just as are the deserts
of Asia and Africa; but in all cases it is believed that the
similar plan of coloration is not due to any affinity but
to their similar needs. The African lizard assimilates in
colour to the sand in and upon which it lives just as does
its American representative. Perhaps, as has been sug-
gested by a competent observer of the birds and beasts of
India’, the huge beak of the hornbill has been produced
in order to assist it in wrenching off from the stem the
often tough fruits upon which it feeds; the toucan may
have got its almost equally large bill by reason of the
same need, Forest country is inhabited by animals that
are adapted to life among trees, whence superficial simi-
1 A Naturalist on the Prowl, by ‘‘ Kha.”
CH. IIT] EVOLUTION AND DISTRIBUTION. 131
larities. It is a matter for the greatest wonder why the
old world monkeys have not got prehensile tails.
On the other hand the similarity of the faunas of
tropical countries even when widely separated have some-
times another explanation. The tapirs of America and
India are unquestionably allied. They are purely tropical
animals and yet separated by a stretch of land which is
not tropical. But in earlier periods of the earth’s history
we know that Europe was favoured with a higher tempe-
rature than at present; we also find the bones of tapirs
in Europe at that period; hence the inference that the
tapir has been isolated in its present habitats by the
gradual decrease of heat in the northern hemisphere.
These few examples again show how needful it is for
the student of Zoogeography to have a thorough acquaint-
ance- with the structure of animals; he must be able to
distinguish between merely adaptative resemblances and
real structural similarities.
Problems of Distribution and Evolution.
It is not necessary now to argue against the doctrine
of special creation; evolution in some form or other is
almost universally accepted ; and the facts of distribution,
as Darwin himself showed in great detail, are among the
most convincing proofs of the untenability of any such
belief as special creation. We have for instance remote
islands, such as the Azores, which are quite capable of
supporting mammalian life, as has been abundantly proved
by the flourishing condition of purposely or accidentally
9—2
132 ROMANES ON DISTRIBUTION. [CH. III
introduced mammalia; and yet these islands are totally
without any indigenous mammalian population. Many
of the forest regions of Africa and Asia enjoy a climate
and temperature like that of the forests of South America,
and yet we do not find them tenanted by an identical
fauna. A locality which is in every way entirely suitable
to the life of a particular animal or plant is by no means
necessarily inhabited by that particular organism. This
of course is not an argument that is necessarily fatal to
the doctrine of creation. But it is at least more intelligible
on the theory of evolution. As the late Mr Romanes
pointed out! we can better understand that the 400 or so
species of humming-birds are limited to the warmer parts
of America because they came into existence in that
continent, and are too feeble in organisation to traverse
the intervening seas which separate them from equally
suitable countries and localities. There is no explanation
except that all these 400 were ultimately derived from
some American parent stock; otherwise why should the
400 if betokening so many distinct acts of creation have
been all of them placed in the same region of the world?
Moreover we are met with the fact that tropical regions
" of the old world with abundant flowers are tenanted by
birds which in some degree resemble the humming-birds
and lead the same sort of life. These again are limited
‘to those regions and are not found in America. On the
doctrine of special creation it is hard to understand why
there should not have been some admixture.
On the other hand if we accept the theory of descent
1 Darwin, before and after. Vol. I., The Darwinian Theory.
CH. IIT] INDEPENDENT ORIGIN OF ALLIED FORMS. 133
with modification we are in a better position to grapple
with the problems offered by the phenomena of the
distribution of animals. Indeed if we hold to the opposite
theory there are no problems for discussion.
But though it is absolutely necessary to believe in
some theory of descent and- modification in order to
explain the facts of distribution, this theory itself presents
some difficulties which will be briefly indicated. It is
usually held that a given species can only come into
existence once; that the same modification can only
appear once and never again. Consequently if we meet
with the same species in two separate localities, there
must have been some time or other communication of
some kind between them; either the animal in question
has been able to traverse the intervening barrier or the
barrier at one time did not exist. If the opposite view
be maintained, and there are some evolutionists who have
maintained it, many of the problems connected with
distribution will at once disappear. Probably a middle
course is here as in so many cases the safer one to follow.
The degree of complication of the changes is in all
likelihood a safe guide to follow. It is for example
inconceivable, as Prof. Lankester has pointed out, that
animals which agree in the possession of that characteristic
_ and. complicated organ peculiar to the Mollusca and
known as the odontophore should not be all of them
genetically related. But on the other hand it is easily
conceivable that two birds might independently lose a
certain muscle; the fact therefore that they were both
without this particular muscle would not be an infallible
134 MEANS OF DISPERSAL. (CH. 111
guide to their relationship. A species of bird or reptile
finding its way to an oceanic island might become darker
in colour. After an interval the parent stock might send
a colony to another oceanic island where the same modi-
fication might well occur, thus exactly reproducing the
first variety ; this view is sapported by Dr Heilprin in his
text-book of geographical distribution, who controverts
Darwin’s suggestion that the same variety cannot be
produced twice, owing to the fact that the parent form
which gave rise to the variety will be supplanted by its
improved offspring, by reminding the reader of the
tenacity of form possessed by certain animals, notably by
some of the Brachiopods, which have persisted unchanged
for many geological periods. Geology also seems to show
that forms do reappear after an interval of total absence ;
but this may be merely another instance of the lamentable
“imperfection of the geological record.” Dr Heilprin
thinks that the tapir which occurs in the Oriental region
and again in the Neotropical may be really the offspring
of two distinct lines from separate tapiroid ancestors; and
that therefore this discontinuity of range does not argue
an extinct parent form, which sent off offshoots from one
continent to the other.
Other geological facts have to be considered which
will be deferred until the next chapter.
Means of Dispersion of Animals.
Animals can extend their range either by active or
passive migration. Both kinds of migration are hindered
by barriers of various kinds.
OH. 111] BARRIERS TO DISPERSAL, 135
A wide expanse of sea is an effectual barrier to the
mammalia and reptilia but not altogether to birds,
especially if there be islands which shorten the stretches
of ocean to be traversed. Even a comparatively small
tract of ocean, in some cases a narrow strait, opposes itself
as an insuperable barrier to some forms of life. The
Amphibia, for example, cannot suffer the contact of sea
water, which is also fatal to their eggs. Earthworms are
also killed by sea water. The narrowest strait is therefore
as efficient a check to the migrations of these animals as
is the widest ocean. High mountain ranges are also
hindrances sometimes quite effectual to the extension of
range of purely terrestrial animals; partly perhaps on
account of temperature but probably more on account of
the physical obstacle. A great expanse of desert is often
as effective a barrier as a tract of sea. The desert of |
Sahara separates two faunas that are widely different.
Changes in climate are also to some extent hindrances,
though not to so great a degree as other barriers. Many
animals can suffer with impunity an arctic or a tropical
climate; the tiger is often regarded as a purely tropical
creature, but as is well known it extends its range to
Amurland, in northern China. At the Zoological Society's
Gardens the polar bears do not show any great mortality ;
a specimen once lived there in perfect health for 37 years.
Travellers have described monkeys leaping among the
snow-clad branches of pine trees upon the Himalayas.
Minute organisms have special facilities for passive mi-
gration. M.de Guerne? investigated the mud adherent to
1 Comptes Rendus, Soc. Biol. 1888.
136 OCEANIC ISLANDS, [cH 111
the feet of wild ducks and found it to contain after
cultivation numerous small creatures such as Nematoda,
Rotifers, eggs of Cladocera, statoblasts of Plwmatella &c.
Not only are the eggs of most of these creatures ex-
tremely patient of desiccation, but the animals them-
selves would readily survive a short journey. A series of
journeys would scatter them far and wide over the globe.
Such small aquatic organisms are known to be widely
dispersed.
We find that the facts of distribution are quite in
accord with these principles. Birds and winged creatures
generally, such as bats, are on the whole the most widely
distributed orders of animals. Amphibia and earthworms»
rarely or never occur on both sides pf a stretch of sea
unless there be good evidence to show that a land
connection once existed. Oceanic islands which have
been formed de novo in mid ocean and are not detached
portions of pre-existing continents are almost invariably
free from such animals as are incapable of traversing the
sea. If sufficiently distant from any continent oceanic
islands are generally without mammals, reptiles and
amphibia, but have both birds and insects and certain
other invertebrates which are transported to them by
involuntary migration.
Influence of geological terrain upon faunas.
Not only the existence of forests or deserts or open
pampas are influential in favouring or checking the
advance of animals to fresh localities; it is even held that
CH. III] GEOLOGICAL STRUCTURE AND DISTRIBUTION, 137
the geological structure of the locality, has a great in-
fluence in the matter. Prof. Edward Forbes held that the
snails were decidedly influenced by such causes in their
range. Limestone is as might be supposed the most
favourable rock for their full development ; but according
to him a sandy soil is better than a clayey or slaty
substratum. Certain apparent exceptions to this general
statement are explained by the greater influence of
climate; thus the Shetland Islands abound in limestone
and yet there is a paucity of shells; on the other hand the
island of Guernsey is populated by vast numbers’ of
specimens of a particular species of snail; this is not due
to the unfavourable granite soil but rather to the favour-
able climate, which is a stronger influence than the soil.
Dr Gadow has recently put forward again the importance
of the geological terrain in affecting the distribution of
organisms. It is much more important thinks Dr Gadow
than temperature or altitude. His studies upon the
subject were made in Portugal, and communicated to the
meeting of the British Association at Bath in the year
1888. They relate principally to reptiles and amphi-
bians; Dr Gadow found reasons for coming to the con-
clusion that for both these groups of animals the red
sandstone was by far the most favourable soil. There is of
course in these two cases no pretence that the soil has a
direct effect comparable to the limy soil which is stated
to be so advantageous to land Mollusca.
138 AQUATIC EARTHWORMS, [CH. III
Dispersal of Oligocheta.
The involuntary migration of animals is mainly con-
fined to the invertebrates and smaller vertebrates. Some
of the former possess special facilities for being carried
about from place to place, and it is invariably the case
that these species or genera are the most widely dis-
tributed. We will commence with a few examples taken
from the terrestrial and fresh-water Annelids. Earth-
worms as already mentioned are not easily moved from.
place to place except by their own exertions; there is
here but little assisted emigration. Rivers it is true
could, and doubtless do, convey them for considerable
distances, as many if not all are capable of surviving a
prolonged immersion in fresh water. M. Perrier kept an
earthworm for some weeks in a vessel of water, and I have
made a similar though not so prolonged an experiment
myself. This however would not be of much use as a
distributing agent unless they were thus enabled to
traverse a desert otherwise impassable. It is possible
that in this way a peculiar genus of earthworms, Stphono-
gaster, distinguished by a pair of long appendages of
problematical use, has been able to pass from tropical
Africa to Egypt, the Nile serving as the path. It is
difficult however to see how earthworms could be conveyed
across the sea!. Floating trunks have been observed far
1 In the case of this as in so many other groups oceanic islands require
more study. Earthworms do occur in oceanic islands, but it seems
probable that such widely distributed forms ‘as Eudrilus eugenie
(St Helena) and Pontoscolex arenicola (Fernando de Noronha) have been
accidentally imported.
CH. 11] DISPERSAL OF OLIGOCHATA. 139
out at sea and they often harbour even large mammals,
which may thus reach a comparatively distant spot; but
unless the water remained absolutely calm during the
long period necessary for the drifting by currents so that
no splashing occurred the worms would probably be killed.
Icebergs on the other hand, which often rise high out of
the water, might conceivably be efficient vehicles for the
transference of these animals. Prof. Leidy found a small
worm frozen in a block of ice which recovered; the worm
was a member of the family Enchytreide, but it is possible
that a small earthworm with a thick body wall might also
survive temporary freezing. The most active agents in
the transference of small animals from country to country
are however birds; but in this case they could be of but
little use. The only way in which a migration of this
kind could be effected would be in the cocoon; earth-
worms invariably deposit their eggs in chitinous cocoons
from which the young do not emerge until nearly adult.
But these are often deposited deepish in the ground, or at
the roots of grass, whence they would not be very likely to
be detached by, and to stick to, the feet of birds. The
case however is different with the aquatic Oligocheta.
These worms are in the first place smaller than the
majority of earthworms, with smaller cocoons, which could
be more readily transported; in the second place they are
deposited often at the margins of pools, where Limicole,
ducks, and other birds are in the habit of dabbling. The
possibilities of successful migration by these means is
increased by the fact that whereas in earthworms it is the
rule for one or at most a limited number of individuals to
140 RANGE OF EOLOSOMA. [CH. III
emerge from a single cocoon, the lower worms often
emerge in great quantities from a single cocoon; a single
cocoon therefore conveyed to a new locality may be the
means of founding a perfectly flourishing colony. The
little genus Molosoma, distinguished by the brilliantly
coloured oil globules with which the skin is ornamented,
has, so far as regards one species at any rate, the power of
temporarily encysting itself’, it has thus a double chance
of carriage to a distant locality at the hands or rather at
the feet of birds. We find that these facts are in
accordance with the actual: distribution of the animals
concerned. Earthworms as a rule are not found in
countries unless there is a reasonable probability of their
having reached them by their own efforts in traversing
the soil, while the aquatic Oligocheta are often very widely
distributed. I have given a few instances of this above.
It has been also pointed out that many of the aquatic
Oligochzeta possess other means of dispersal by birds in
addition to the cocoons. The sete are often such as
would readily adhere to any rough surface, owing to their
hooked and bifid tips and their considerable size in
proportion to that of the body.
Dispersal of land and fresh-water Mollusca.
This subject has been so recently and fully treated by
Mr Kew’ that it is only necessary to make a few extracts
from his book. The extension of their range on the part
1 Cf, Ann. and Mag. Nat. Hist. Jan. 1892, p. 12.
2 The Dispersal of Shells, Int. Sci. Series, London, 1893.
CH. II] ' MOLLUSCA OF PONDS. 141
of fresh-water Mollusca can be studied in its most simple
aspect by a consideration of the faunas of artificial ponds
and of “dew ponds.” The latter are, it should be explained,
artificial ponds dug and lined with concrete or chalk mud
for the convenience of cattle; they are left to be filled by
rain, dew, and the condensation of mist. At first devoid
of inhabitants such ponds gradually become stocked, thus
proving a capacity for active or passive migration on the
part of the Mollusca. Careful and successive observations
have proved in a few cases the actual time in which a
given pond may become populous. An isolated pond
near Leeds investigated by Mr Nelson during the years
1860-63 yielded two bivalves, Spheriwm lacustre and
Pisidiwm pusillum, and two Gastropods, Planorbis nautilus
and Lymnea peregra. About 1873 an additional species,
Planorbis corneus, was discovered; and finally ten years
later the Molluscan fauna was increased by six other
species. Now this particular pond was in no communi-
cation even in seasons of flood with any other pond or
stream; hence its inhabitants must have arrived by some
other conveyance than running water. To be able to
travel at all, and we shall enquire immediately into the
means of dispersal, implies considerable tenacity of life,
principally in withstanding the fatal effect of a too thorough
desiccation. That this tenacity of life need not by any
manner of means be underestimated in dealing with the
problem under review, is shown by the fact that an
Australian Unio “having already survived in a dry drawer
for 231 days, packed up (after being tested in water) and
forwarded to England, reached Southampton in a living
142 MIGRATIONS OF MOLLUSCA. [CH. Ill
state 498 days after its capture.” This may serve as a
sample from a rich store of instances.
Some aquatic Mollusca leave the water and travel over
the fields. This is the case for instance with Lymnaea
truncatula. Those that are not able in this way to travel
from pond to pond have to trust to vehicles which may be
animate or inanimate. Whirlwinds have been proved to
take up and deposit safely at a distance shoals of little
fish; and not only fish but Mollusca—a thundercloud at
Paderborn in Germany rained down crowds of the fresh-
water bivalve Anodonta anatina. More effective in ex-
tending the range of such Mollusca are birds and insects.
Canon Tristram on one occasion shot a mallard in the
Sahara to the feet of which were attached “the eggs of
some Mollusc—probably Succinea.” Mr Darwin proved by
suspending a duck’s feet in an aquarium that the newly
hatched young of univalves will adhere, and might there-
fore be carried long distances. But on the other hand
there is little positive evidence that such a means of
transit is made use of in nature. Mr Kew enquired with
negative results from a large number of our leading
ornithologists whether shells had actually been found
adherent to the feathers or legs of birds. As a mere
matter of probability everyone is agreed that this method
of transit is feasible; suggestions as to how it may take
place are unfortunately considerably in excess of records
of the actual event. Insects however have often been
taken with bivalve shells actually adhering to them; “five
individuals at least,” says Mr Kew, “ of the water scorpion
(Nepa), a large flying bug, have been caught with shells
CH. III] DISPERSAL OF MOLLUSCA BY INSECTS, 143
attached.” The great water beetle Dytiscus has also been
proved to aid in the dispersal of fresh-water Mollusca,
while the small Motonecta, the “water boatman,” belongs
to the same category. These insects are powerful fliers
and could certainly get from pond to pond even when
weighted with a small bivalve. It is bivalves that they
have been proved to convey, not univalves. Birds, newts
and toads have also been shown to act as the means of
dispersal of Lamellibranchs. The fact that these can and
do snap at and hold tight to any object that is thrust
between the two valves of the shell ensures their dispersal
in this way.
The above facts enable us to understand the peopling
of isolated ponds. The distances to be traversed are so
small, that the means of dispersal appear to be quite
adequate. We now come to the more difficult question of
crossing arms of the sea or, it may be, wide tracts of
ocean. We must consider also the terrestrial as well as
the aquatic species. That both classes of Mollusca do
cross even the widest seas is shown by their occurrence in
oceanic islands; that this occurs but rarely is shown by
the peculiarities of oceanic island Mollusca as compared
with those of the nearest mainland, whence they have
been presumably colonised. It is noteworthy however
that those who know most about the group invoke a
former land connection where possible. Thus the Rev.
A. H. Cooke in considering the rich fauna of land Mollusca
of the Philippine Islands’, so varied upon the different
1 P.Z.S. 1892, p. 447.
144° HELIX DESERTORUM. (cH. 111
islands, discusses the problems offered entirely from the
point of view of former land connection.
Such land Mollusca as are operculate can of course
close their shells and so endure with impunity events that
would be fatal to others; even the temporary operculum
formed by Helix is effective in this way. It is important
too to notice that. fresh-water Mollusca can in some cases
endure brackish water, but it-is stated by both Darwin
and Wallace that adults and ova are immediately destroyed
by salt water. This is of course fatal to the theory that
floating timber and brushwood can convey fresh-water
Mollusca in safety from shore to shore. Ice on the other
hand may well be carrier; Anodonta and Succinea and
Paludina have been frozen and have survived after libe-
ration. With regard to land Molluscs their tenacity of
life has become almost proverbial through the famous case
of the Helix desertorum in the British Museum. More
important is the record that out of 100 land shells im-
mersed in the sea in a box pierced with holes for a
fortnight 27 recovered; but of these 11 (out of a total of
12) were the operculate Cyclostoma. Helia however may
sometimes survive a similar treatment.
In this way it is possible, or, according to Prof.
Semper’, likely that ocean currents propelling tree trunks
or even “floating islands” such as are known im tropical
seas may have effected the dispersal of land shells. But
in such cases it must be often necessary that the Molluscs
in question had secreted themselves in the crevices of the
bark of trees, a habit which has been apparently assigned
1 Animal Life. Int. Sci. Series.
CH. IIt] ARION AND TESTACELLA. 145
to them without too much reason. Animal agencies for
the dispersal of both land and fresh water shells for long
distances across the sea are practically limited to birds;
and as has been already mentioned this method of trans-
port must be rare as it has been so seldom observed. The
dispersal of slugs is of course harder to understand than
that of snails, as they have no protective shell. And yet
they are found in such remote islands as New Caledonia,
New Zealand, the Auckland Islands and some of the
Mascarene Islands. Madeira and the Azores have Arion,
which Mr Cockerell says’ “has some appearance of being
native,” though he makes the significant additional remark
that’ “none of the species are peculiar.” The slug Testacella
makes a temporary cocoon, as do the land planarians and
some earthworms, in which no doubt it can survive drought.
But this will not sufficiently account for dispersal over
the sea; and sea water is fatal to slugs and their eggs.
The eggs however are sometimes deposited in hollow
trunks of trees, where even the animals themselves occa-
sionally hide. The various methods of migration used
by other Molluscs may possibly be effective in the case of
slugs; but at present there is here more than anywhere
a lamentable want of actual fact.
Dispersal of Amphibia.
The migrations of the larger aquatic animals are more
difficult; and yet they have not unfrequently.a wide
1 Geographical Distribution of Slugs. P.Z.S. 1891, p. 214.
2 Cf. p, 152.
BZ. 10
146 THE EDIBLE FROG. [cH. III
range, which means power of dispersal. The edible frog,
Rana esculenta, is a case in point. This species extends
from Great Britain, where however it is supposed to have
been introduced, in the West to Corea and Japan in the
East and to Algeria in the South. Its range in fact is
over the entire Palearctic region; but individuals from
Siam agree with Japanese specimens, so that the frog is
Oriental as well as Palearctic in habitat. In a paper
upon the distribution of this frog Mr Boulenger’ quotes
14 synonyms, generic as well as specific, thus illustrating
the difficulties introduced into the study of geographical
distribution by imperfect acquaintance with zoological
fact. Intermediate forms however prove that there is but
one species, divisible into four varieties. It is a question
whether certain of these varieties which occur in the
same country and do not interbreed are not rather of
specific than varietal value; but in any case they must be
derived from the same stock, and the eastern variety does
not overlap any of the western. These facts seem to
argue powers of extended migration hampered by infre-
quent opportunity. A river system appears to be, at least
as a rule, inhabited by an identical fauna throughout,
though its course may be, as is that of the Nile, from
tropical to temperate regions. But river systems are
isolated from each other by intervening mountains; and
moreover the rapid streams at the source are not suitable
for Amphibian life; hence a species which inhabited one
river system would not in the ordinary course of events
get within a measurable distance of the tributaries of
1 P.Z.8. 1891, p. 374.
CH. III] MIGRATIONS OF REPTILES. 147
another river system. We can only understand the min-
gling of the faunas of two river systems by wide-spreading
floods or by alterations in mountain ranges. Mountain
ranges are necessarily modern, geologically speaking,
owing to the potency of the effects of subaerial denudation.
Different relations existed in river systems before their
upheaval; and it is probably to facts of this kind and
possibly also to whirlwinds that we must trust in reflecting
upon the migrations of the Amphibia, which cannot be
much carried about by birds, as they are absent from
oceanic islands’, even so close to the mainland as is
Fernando Noronha.
Dispersal of Reptiles.
‘It will be pointed out later that as a rule the only
terrestrial vertebrates of purely oceanic islands, if there
are any at all, are Reptiles. This necessarily argues that
Reptiles possess some power of crossing the sea which is
denied to other vertebrates. There are a certain number
of facts which favour this view. While there are com-
paratively few mammals which voluntarily take to the
sea, there are not a few reptiles which either live almost
habitually in sea water without any corresponding modi-
fication of structure, or which occasionally are met with
in salt water.
1 There is however Bufo dialophus of the Sandwich Islands; it may
be that the strings of eggs produced by the toad are more portable by
birds than-the masses of eggs.of the frog.
10—2
&
148 MARINE CROCODILES. (cH. III
Coupled with this series of facts, which will be dealt
with immediately, there is the tenacity of life of reptiles to
be constantly borne in mind. The most familiar example
of a Lizard which is almost entirely marine is the remark-
able iguanoid Amblyrhynchus of the Galapagos. Not
only does this lizard take long swims out to sea but it can
evidently only be drowned with difficulty. Darwin made.
the experiment of sinking one to the bottom for several
hours, at the conclusion of which it appeared to be
uninjured. It is even a question whether the animals
may not possibly be able to respire oxygen dissolved in
sea water; at any rate it seems certain that some other
reptiles, e.g. certain tortoises, can. The pharynx of a few
species, for instance the water tortoise Aspidonectes, is
provided with filamentary appendages, apparently attached
to the remains of the gill arches, which are full of blood
vessels and which enable the creature to breathe; at any
rate this tortoise has been kept under water for the space
of 10 hours. It is held that these vascular tufts are the
homologues of the gills of the Amphibia, and it is quite
conceivable that this capacity for breathing oxygen dis-
solved in water may have been inherited by other reptiles
besides the tortoises.
Apart altogether from theories there are other reptiles
besides the Amblyrhynchus which can swim with impunity
in sea water and which do so on occasions.
The crocodiles of the present epoch are entirely fresh
water in habit; but the majority of the extinct families
were on the contrary marine. From the ancient Belodon
downwards we meet with the remains of the crocodiles in
CH. UT] REPTILES AND OCEAN BARRIERS. 149
marine strata, which in all probability indicates that they
were at least frequently in the habit of swimming out to
sea. It is not of course positive proof, for it might be
urged that we have to do merely with the remains of
crocodiles which had been washed down the rivers after
death. The interesting point in connection with these
habits of the more ancient crocodiles is that many living
crocodiles will take to the sea sometimes; a crocodile has
been met with at a very long distance from land—within
the last year or two a crocodile has been recorded at the
Cocos Islands, which must therefore have swum for a con-
siderable distance.
Not only are there purely marine snakes, like the
poisonous Pelamys, but serpents which are habitually
terrestrial will make an occasional trip to sea. It is
stated the snake Tropidonotus tessellatus (allied to our
common Grass snake) which lives upon the shores of
Dalmatia will enter the sea. Even the cobra (Nata
tripudians) has been captured entangled in the anchor
chain of a ship’. Fresh water tortoises are by no means
always impatient of salt water. And finally as many
lizards and probably all snakes can swim in fresh water it
is quite a reasonable supposition that in some cases they
could survive a sea voyage.
With these examples before us it is clearly incorrect
to say that lizards and serpents are incapable of passing
ocean barriers, which indeed their presence on oceanic
islands shows conclusively that they can do. Mr Wallace
while admitting that lizards possess some means of
1 Cf. Simroth, Die Entstehung der Landthiere.
150 FREQUENT AND INFREQUENT MIGRATION. [CH. III
dispersal across the sea thinks that this migration is
effected involuntarily and in the egg state. As to in-
voluntary migration on the part of reptiles Mr Wallace
quotes the case of a boa constrictor which floated on a
cedar to the island of St Vincent, two hundred miles away
from its home, where it killed a sheep before it was itself
put an end to.
Evidence of capacity for Migration on the part of
a given animal.
As Prof. Semper has acutely pointed out’ the facilities
for migration possessed by an animal can be to a certain
extent measured by the amount of modification gone
through by obviously migrated individuals. Naturally
no clearly defined scale can be drawn up; but if an
animal, say a Mollusc, can very readily cross the sea to an
oceanic island it will be likely that its descendants upon
the island will hardly, if at all, differ from the parent
stock upon the main land. The reason of course is that
migration being easy will be constant and frequent, thus
preventing the acquisition of new characters through
isolation ; the perpetual interbreeding with newly arrived
individuals of the parent race will securely keep the
progeny in the original mould. Of course other causes
must also come into play, but this fact cannot be without
significance.
It has been already pointed out that Reptiles are rare
1 Animal Life, Int. Sci. Series.
CH. IIT] BIRDS OF OCEANIC ISLANDS. 151
on oceanic islands; indeed they are more often entirely
absent than present even in small numbers; hence it
must be inferred that they have peculiar difficulties in
crossing a considerable expanse of ocean. When they are
met with upon oceanic islands, as for example in the
Galapagos, they have undergone considerable modification,
thus emphasising from another point of view the diffi-
culties of their transference. On the other hand birds
are of all animals the most liberally endowed with the
capacity of crossing long stretches of ocean; correlated
with this the birds of oceanic islands are not always
greatly modified as compared with their nearest ‘allies
upon the mainland; this is particularly well shown in
such birds as are in the habit of taking long flights; the
Waders for instance of oceanic islands are but rarely of
different species from those of the adjacent continents.
On the other hand the finches and such like “ small birds,”
frequently arboreal, depending entirely or largely upon
vegetable food, and not in the least marine in their
proclivities are commonly much specialised upon oceanic
islands; often indeed to, such a degree that their affinities
are hard to interpret, as is particularly well shown in
the case of some of the Sandwich Islands’ birds (for which
see below).
Influence of human interference upon Migration.
In considering the facts and problems of distribution
it is very important to eliminate the changes in faunas
152 MAN AS A DISTRIBUTING AGENT. [CH, IIT
due to the interference of man. Such islands as St
Helena have had their fauna and flora radically changed
by these means.
But there are other cases in which man has probably
had an influence which are not quite so obvious as that
just cited. Many small land Mollusca are readily carried
by ships laden with timber or other material upon which
such animals are found; and the same kind of argument
applies to numerous other cases. When therefore we find
an identical species upon the two sides of a wide ocean
or other barrier hardly to be crossed by the animal in
question, we must not at once assume that this is evidence
of past land connection, or of unsuspected facilities for
crossing the barrier; it may be merely a question of
transport by ships. A consideration of the distribution of
certain genera of earthworms will serve to illustrate the
kind of argument and tests which may be applied to sift
these cases.
The continent of Europe, and, so far as it is known,
northern Asia and the whole of North America is chiefly
tenanted by members of the genera Allurus, Allolobophora
and Lumbricus. There are but few other genera than
these met with in the regions named. But these same
genera also occur in every other part of the world. They
are abundant for example in South America and in New
Zealand. A gathering of earthworms from tropical regions
is in fact, so far as my own experience goes, rarely without
Lumbricide. This might be urged as an argument for
the antiquity of this particular family; but as a matter of
fact the structural relations of this family to others seems
CH. IIT] EXTRA-EUROPEAN LUMBRICIDA. 153
rather to indicate that it is modern. Indeed the world-
wide distribution of the three genera is really in all
probability due to the interference of man and not to
their own unaided efforts. The reasons for this are
twofold. In the first place it is important to show that
accidental transference is possible. This is shown by the
fact that Wardian cases received at the Royal Gardens
Kew frequently contain earthworms which have been
included accidentally.
In plenty of other ways could specimens be conveyed
in this way from one country to another. Now were the
occurrence of the same genera in so many and so distantly
separated parts of the world a fact due to natural causes
alone, we should expect to find some differentiation of
species. But this is precisely what we do not find.
Without a single exception’ the Lumbricide from extra-
European regions are identical with those of Europe;
there is not even a variety known which is characteristic
of a foreign continent. This is an argument of great
force ; if‘ this dispersal were of old standing, as it must
have been were it brought about by purely natural causes,
time would have elapsed to allow of some modification in
various directions. The second argument is derived from
a consideration of the actual range of the presumably
imported species in the country of their adoption. Dr
Michaelsen has pointed out that in South America, where
Lumbricide are very abundant, they are most abundant,
in cultivated ground near to the coast, nearest to the point
1 Unless Allolobophora Japonica. But of course Japan belongs to
the Palearctic region.
154 PAST AND PRESENT RANGE OF THE BEAR, [CH. II
of disembarcation ; the further we recede from the coast
the rarer do the European Lumbricide become; in the
interior of South America they are not to be seen. Prof.
Spencer met with exactly the same state of affairs in
Australia; the gardens in the towns abound in Lumbri-
cide to the almost entire exclusion of the truly indigenous
forms; to find these the cities must be left behind. The
coincidence is too great to be passed over. This leads to
the inference that in the case of these particular genera
the forms met with outside the Palearctic region—perhaps
even including North America—are due to carriage on
the part of man. Every case of a supposed wide distribu-
tion of a species should in the same way be submitted to
careful criticism before acceptation as a fact of distribution.
Mr Macpherson’s record! of an African lizard in Cumber-
land and Dr Gray's statement of a young crocodile
hidden beneath a haystack need no special examination
to deny their claims to indigeneity; but there are plenty
of cases like that of the earthworms just referred to.
On a former page we have dealt with discontinuous
distribution as a phenomena explicable in various ways.
An excellent instance of the discontinuous distribution
of a species due to the influence of man is afforded by the
common bear (Ursus arctos) of Europe. And here we
can, which we could not in the last case, fill up the gaps
for ourselves with certainty and not merely with reason-
able probability. In a carefully coloured map illustrating
the distribution of the bear-like Carnivora Dr Grevé?
1 The Natural History of Lakeland.
2 Zool. Jahrbiicher, Vol. v1. Abt. f. Syst.
CH. 111] THE LYNX AND THE BEAR IN EUROPE. 155
tints nearly the whole of the Palearctic region with the
colour which he uses to express the range of this Carnivora.
He also indicates the tract of country from which this
bear has died out within the historic period. At the
present time there are several isolated patches to the
west and south of the country continuously occupied by
the animal, where it is still to be met with; such as the
Pyrenees and a portion of Switzerland. These isolated
patches are in most cases connected with the main area
by regions from which the animal has recently retired.
Another map illustrates precisely the same kind of distri-
bution exhibited by the lynx. This animal has a range
almost co-extensive with Ursus arctos, but it does not
get into Japan, which the bear does. It persists as two
outliers in Western Europe almost exactly corresponding
to those of the bear. But a tract on the east coast of
Italy no longer inhabited by the lynx is still the home of
the bear. Cultivation and civilisation are no doubt the
cause of these gaps; but it is curious that they should
have been more effective in the case of the smaller lynx
than the larger bear.
The existing Distribution of land and sea considered
in relation to Zoological Geography.
In considering the phenomena of distribution at the
present day, it is important to bear in mind that the
existing distribution of land and sea has on the whole
remained the same for very long periods, according to
some for as long a time as we have any cognizance of.
156 THE PERMANENCE OF OCEANS. [CH. 111
There are, it is true, those who would evolve a continent
to account for the range of a genus of beetles; but on the
whole the evidence is against any such radical views of
past changes in the positions of oceans and continents.
The superstition of Atlantis connecting Africa and America
has perhaps not quite died away; and Mr H. O. Forbes
would relegate the tropical island of Madagascar, not to
mention the colder and more southern regions, to the icy
clasp of the Antarctic continent.
Evidence in favour of Permanence of Oceans.
The evidence in favour of the permanence of oceanic
area as such has been recently summed up by Mr Blan-
ford’. The arguments are fourfold.
I. It has been ascertained that the density of the
earth’s crust below the deep oceans is greater than that
elsewhere. This leads to the inference that this has been
so always, because denudation, if the ocean bottom had
been ever dry land, would have removed this inequality.
The detritus washed away by the action of rivers, rain,
and such causes would have tended to equalise the density
of the land everywhere. Mr Blanford however points
out in criticism of this suggestion that the observations,
due to Archdeacon Pratt, were made only in the Indian
Ocean, and may perhaps not hold universally. The
argument therefore is not of that weight which may be
fairly attached to some other considerations.
1 Presidential Address to Geological Society, 1890.
CH. III] OCEANIC ISLANDS AND SUBMERGED CONTINENTS, 157
II. It seems to be well ascertained that no oceanic
islands are formed of stratified rocks belonging to early
geological periods. They are in the main either of recent
voleanic or coral formation. Sir Archibald Geikie in
reviewing the Abbé Renard’s petrological work upon the
rocks of the island of St Paul in the Atlantic in Nature
some years back entitled his review, “A search for a lost
continent with a microscope.” But no amount of research
either with or without a microscope has ever revealed the
slightest traces of a pre-existing continent in the oceanic
islands of any of the great oceans. On the other hand it
has been found that certain islands, once regarded as
purely oceanic, are in reality not so. This is the case
for example with New Caledonia, which contains both
palezozoic and mesozoic rocks, though it is isolated by
water exceeding 1000 fathoms in depth. But these few
instances do not invalidate the general conclusion. Yet
two possible criticisms must be borne in mind; in the
first place we are not as yet in possession of all the
requisite knowledge about all the islands in question ; in
the second place we can imagine a subsidence of a large
continental tract which would leave above the surface of
the water no trace of its continental origin. If Africa, as
Mr Blanford points out, were to be submerged 2000
fathoms below the sea only a few elevations would remain ;
these are Mt Kilimanjaro, the Camaroons, and a few
other peaks; these mountains it must be remembered
are purely volcanic in structure and would give no
clue to the fate which had overtaken the surrounding
land.
158 CHALK AND OOZE. [cH. IIT
III. The third argument is of equal force, or perhaps
of greater force, than the last. If the great ocean depths
have not always been permanent we should expect to
meet with, among the stratified rocks, evidence of deep-sea
deposits. Here again defective knowledge offers a way
out of the difficulty to those who choose to believe in a
thorough change from time to time of the existing
relations between continental areas and the great oceans ;
the fact that no continental deposits present any likeness
to deep-sea “oozes” and “clays” seems to prevent the
holding of such a theory; but the matter requires to be
more thoroughly disproved. An exploration of certain
geologically little known tracts might reveal evidence in
favour of the view which is at present not forthcoming.
It was at one time held that there is a great likeness
between the chalk of the Mesozoic epoch and the globi-
gerina, ooze now in course of deposition in certain tracts of
the ocean. Superficially this resemblance is not a little
striking; but a closer comparison dissipates the theory.
It is true that in the deep sea—in regions where the
globigerina ooze is found—certain animals exist which
are identical with or very closely allied to animals
characteristic of the chalk. The Echinoids with flexible
tests, numerous Cidarids, and the species of the Globi-
gerine themselves bear out this statement. A careful
analysis however of the chemical composition of the ooze
and a comparison of the results thus obtained show
divergences which are of importance. The percentage
of carbonate of lime in chalk is from 94—98°/,, while
CH. IIT] OOZE OF SHALLOW WATER. 159
in ooze from a depth of many fathoms in mid-Atlantic it
is only 43—79°/,. Chalk has a very small quantity of
silica, alumina and insoluble débris, while in ooze there
is 10—43 °/, of these substances.
IV. Dr John Murray found that the ooze from shallow
water resembles chalk much more nearly than that from
depths. over 1000 fathoms. Prof. Agassiz has described a
shore deposit largely derived from the débris of coral rocks
which bears a very close resemblance to chalk; and it is
possible that the chalk of Europe was to some extent at
any rate formed from the denudation of the coral reefs
which were so abundant during the oolite period. The
most striking instance which appears so far to support the
contrary proposition is the Radiolarian earth of the
Barbadoes, and perhaps of some of the other West
Indian islands. This overlies unquestioned sandstones
of tertiary origin; hence it follows that, since the be-
ginning of the tertiary epoch, the land immediately
surrounding those islands and the islands themselves
must have been depressed to a depth of at least 1000
fathoms.
Evidence against the view that existing Oceans
have not largely changed their areas.
There is another series of facts which have a bearing
upon the problems at issue, and which indicate, though
obscurely perhaps, a possibility that far back in time
there may have been a relative disposition radically
different from that now prevailing.
160 RANGE OF GRAPTOLITES. (CH, III
That this may have been so is suggested by two con-
siderations deduced from two classes of facts. In the first
place the former wider range of organisms than now is
well known. This has been held to imply a former pre-
dominance of more uniform conditions of temperature
and climate, but it may also perhaps be looked upon as
evidence of another kind, which we shall now enter into.
I quote from Prof. Heilprin’s manual the fact that out
of 13 Silurian and 24 Devonian Brachiopods found in the
deposits of China 10 of the former and 16 of the latter
occur in European formations, a proportion which is not
only very striking, but almost inexplicable on the hypo-
thesis that the conditions of marine life in the several
regions were then precisely as now.
Another example may be taken from the Graptolites.
This is a particularly useful example, for it enables us to
make use of the dilemma. It has been suggested that
the Graptolites flourished in deep water and that the
rocks which contained them are therefore true deep-sea
deposits. If this is admitted, then the question is settled
at once without any necessity to proceed further. But
if not, we have to account for the striking fact that out
of the 24 species of Graptolites from Australia no less
than 18 are species belonging to Canada and the United
States.
Now we may contrast with the conditions that ob-
tained during the Palzozoic period those which obtain
at the present day. And the contrast is most thorough.
Prof. Heilprin remarks that out of “the 400 or more
species of molluscs inhabiting the Japanese waters it
CH. 111] ANTARCTIC CRUSTACEA. 161
appears that not more than 20 are found on the west
coast of North America.” The proportion, in fact, instead
of being three-fourths is one-twentieth. It will be re-
membered also, in estimating the significance of these
facts, that the coasts of Japan enjoy a climate and tempe-
rature that is not widely different from that which is en-
joyed by the coasts of the part of America brought into
comparison.
We may take as another example the Isopod Crusta-
ceans of the antarctic region which have been investi-
gated by the “Challenger,” “Gazelle,” and recently by the
German Polar expedition, the results of all these expedi-
tions having been carefully reported upon by Dr Pfeffer.
He enumerates 55 marine species of which only five have
at all an extensive range, and two of these, which are
stated to inhabit at once the shores of Patagonia and of
Rio Janeiro, are queried. As to a more northward ex-
tension there are no species which show any signs of it.
The genera enumerated are in all 27; and out of these
11 are limited to the southern ocean in the antarctic area.
So much then for the first series of facts, which is that
the wide past distribution of marine animals contrasts
with the present limited distribution of the same, even
along areas which have very similar climatal conditions.
Many geologists, including Mr Mellard Reade’, have
pointed out the extreme similarity between the con-
temporaneous or supposed contemporaneous rocks in
different parts of the world. When we “consider the
rocks,” says the last-mentioned observer, “constituting the
1 Natural Science, 1894.
B. Z. Il
162 SEAS OF CARBONIFEROUS PERIOD. [CH. IH
Carboniferous formation, the persistence of characteristics
over large areas of the earth’s surface is most ‘striking.
The repetition of coals, sandstones and shales in the
Carboniferous rocks of the North American continent
and. in that of Great Britain seems almost to point to a
common origin.” And this is by no means the only
example that could be adduced of the closest lithological
analogies between contemporaneous rocks in widely sepa-
rated localities. .
These two series of facts almost seem to lead-at once
to the conclusion that we have here evidence that in, say
the Carboniferous period, there was a tract of ocean con-
tinuous from east to west of not great depth, which would
point to adjacent land and set aside the theory that the
deep oceans of to-day have always been practically the same.
But there are some criticisms to consider first. It has
been objected to the question of contemporaneity, let
alone the continuity, in a given formation that it is im-
possible strictly speaking, since organisms take time to
migrate. A given species comes into existence let us
suppose in the Australian district; it has to get to the
European seas where it may be also found; the time that
elapses while this journey is made is longer or shorter ac-
cording to the distance and to the variety and difficulty
of the obstacles. “For anything that Geology or Paleonto-
logy is able to show to the contrary,” wrote Prof. Huxley,
“a Devonian fauna and flora in the British Islands may
have been contemporaneous with Silurian life in North
America and with a Carboniferous fauna and flora in
Africa.”
CH. IT] SYNCHRONOUS FAUNAS, 163
In this case it would necessarily follow, on account of
the disparity of age, that there need be no similarity in
conditions between the different parts of the world during
the same geological period. Prof. Nicholson’, accepting
this criticism, observes, “Most of the facts bearing upon
this question may be elicited by a consideration of such a
widely extended and well-known formation as the Moun-
tain Limestone or Sub-Carboniferous Limestone. This
formation occurs in localities as remote from one another
as Europe, Central Asia, North America, South America
and Australia; and it is characterised by an assemblage
of well-marked fossils, amongst which Brachiopods be-
longing to the genus Productus may be specially singled
out. Now if we believe that the Carboniferous Limestone
in all the widely distant localities was strictly contempo-
raneous, we should be compelled to admit the existence
of an ocean embracing all these points, and in spite of its
enormous extent so uniform in temperature and depth
and the other conditions of marine life, that beings either
the same or very nearly the same inhabited it from end
to end.” These two statements are ingeniously met by
Prof, Heilprin. They imply, he says, that every animal
has migrated in exactly the same way and direction.
And it is hardly conceivable, in fact impossible, that this
can have been everywhere the case. “Given the possible
equivalence in age, as is argued, of the Silurian fauna of
North America with the Devonian of the British Isles,
and the Carboniferous of Africa or any similar arrange-
ment, why has it never happened that when migration,
1 Manual of Paleontology.
11—2
=
164 ANTARCTIC CONTINENT. [CH. I
necessitated by alterations in the physical condition of the
environs, commenced, a fauna with an earlier facies has
been imposed upon a later one, as the Devonian of Britain
upon the Carboniferous of Africa, or the American Silurian
upon the British Devonian?” The migration of one
animal might have been in one direction and the migra-
tion of another in the reverse direction.
Besides the migration of animals can hardly be sup-
posed always or often to occupy a space of time that
could be fairly compared to a geological period. Especially
is this the case with marine creatures whose powers of dis-
persal are so much greater than those of terrestrial animals.
The Indo-Pacific fauna for example is widely spread at
the present day; and formations now being laid down at
the extremities of this vast area are not only synchronous
but will entomb the remains of largely similar organisms,
often of identical species.
These general considerations lead to the discussion of
the following particular examples of a possibly greater ex-
tension of land in past times through what is now deep sea.
Evidence in favour of a formerly more extensive
Antarctic Continent.
Faunal conditions in the southern hemisphere have
recently been applied again to the question of a former
northward extension of the antarctic continent. The
evidence has been brought together by Mr H. O. Forbes?.
1 Proc. Roy. Geog. Soc. 1894,
CH. 111] FORMER EXTENSION OF ANTARCTICA. 165
The continent at present is entirely ice-bound, and
though of great size, about twice as large as Europe, does
not bulk largely upon most maps; this is due to the small
extent of coast line which has been explored. At present
the antarctic continent is probably almost entirely with-
out a terrestrial fauna by reason of course of its rigorous
climate.
Mr Forbes boldly draws imaginary land tracts connect-
ing this region with the adjacent continents of Africa,
America and Australia. There is certainly some evidence
in favour of such a connection having once existed. There
are however numerous facts which appear to negative
such an idea. The negation however is possibly more
apparent than real. It has been pointed out that the
ocean which separates the south polar continent from any
other land is of great depth, and all those arguments for
the permanence of the great oceans apply in this case as
in the others dealt with on a previous page. But it must
be admitted here as in so many cases that our knowledge
of ocean soundings is far from complete; Mr Blanford
points out’ that south of Africa there are no soundings
and that therefore we are at liberty in the meantime to
regard as possible the existence of a bank uniting the
two continents of no greater depth than the Mozambique
channel. It is however rather New Zealand and Pata-
gonia which are allied in their fauna than either of them
with the southern parts of Africa; resemblances between
tropical Africa and tropical America have been dealt with
on another page (p. 112). These likenesses in a few cases
1 Presidential address to Geol. Soc. 1890,
166 PENGUINS. [cH. It
amount to positive identity of species; and moreover of
species whose identity is exceedingly remarkable in rela-
tion to the problem offered for solution.
That the Penguins should extend throughout the
whole antarctic area from New Zealand to Patagonia is
not so remarkable a fact; there is no need of evolving
a continent for the convenience of these almost marine
birds, or even to explain the wide range of the purely ant-
arctic Chionis. Nor do the arguments, such as they are,
which are to be derived from a study of the range of the
living “struthious” birds appear to have overwhelming
force; both Penguins and struthious birds are in all pro-
bability the remnants of ancient types; and their relega-
tion to the southernmost half of the globe is as much
in accord with the polar origin of life dealt with elsewhere
as with a former extensive antarctic continent. Besides
the struthious birds are not now regarded as belonging
to one family; they seem really to form an assemblage
of the remains of more than one family. The distribution
of the struthious birds both living and extinct may
be brought forward as evidence of the former north-
ward extension of the antarctic continent. Recent dis-
coveries in the Argentine have an important bearing upon
the matter; the evidence takes us back to the middle and
even to the beginning of the tertiary period; this how-
ever is nothing to be surprised at; the connection between.
the existing land masses and the antarctic continent, if it
ever existed at all, must have been very ancient, as the
stretch of ocean now dividing them is so wide. As is
unfortunately: the rule with extinct species known by
CH. 111] STRUTHIOUS BIRDS. 167
remains which are in various degrees fragmentary, the
actual number of the genera and species is doubtful; but
it seems now to be well established that there were in the
more southern regions of the American continent at least
three genera of gigantic flightless birds comprising seven
or eight species. To these genera the names of Brontornis,
Phororhacus and Opisthodactylus have been applied. Some
of these birds were actually the largest known forms of
Ratites. It appears from certain roughnesses on ‘the
bones of the skull that some species bore upon the head
a casque like that of the Cassowaries; though in some
respects, thinks Mr Lydekker, the resemblances are with
the living and South American Psophia and Cariama'.
They approximate however to the Dinornithide in a
number of characters which together are of some. im-
portance; thus there is with them as in the Dinornithide
a bony bridge over the extensor groove of the tibia, and
the general proportions of the tibia and tarso-metatarsus
are like those of the same bones in the: Dinornithide.
But the significance of the facts from the point of view
of Zoogeography is somewhat blurred if we rightly refer
to the Ratites, or Platycoracoide, as Fiirbringer calls
them, the European genera Gastornis and Dasornis and
the American Diatryma. Fiirbringer however queries
the inclusion of the two last in the group, and does not
allow Gastornis there ‘at all. Dasornis is only known by
an imperfect cranium, and Diatryma by an incomplete
tarso-metatarsus, so that this evidence is not at present
-1 See-a paper.by Lydekker in Ibis for 1893.
168 TERRESTRIAL ANNELIDS. [CH. III
necessarily fatal to the evidence offered by the un-
doubtedly struthious Argentine birds.
As with the Sea-lions, also practically confined to the
southern hemisphere, the explanation of the range of
the Penguins is possibly rather one of temperature. The
Sea-lions are strong swimmers, and have been met with
far from land; indeed the “ Sea-serpent ” is possibly partly
compounded of a large sea-lion. Currents too would assist
in the dispersal of these animals without any recourse to
a continuous coast-line to aid in migration. M. Milne
Edwards, whose name is particularly to be associated with
the idea of an antarctic region, has pointed out that
marine currents flow from the polar region in all direc-
tions northward ; with the aid of these currents, reinforced
by floating ice, which is known to reach land abutting
upon the southern ocean, we can understand the peopling
of Kerguelen and other regions with the birds and
mammals referred to. Mr Wallace while naturally ad-
mitting the resemblances between various tracts of land
in the southern hemisphere is disposed to rely upon float-
ing masses of ice to account for the facts. It is difficult
to apply this solution of a puzzling problem to the case
of the terrestrial Annelida of the antarctic area. It is a
curious fact that Mr Forbes with the material before him
did not use the strongest argument that could be used
in favour of his views; since those papers were written
the evidence has moreover increased. The earthworm
fauna of New Zealand is perhaps as well known as is that
of any extra-European region. That our knowledge is
approaching completion is shown by the fact that collec-
"gg1 °¢ anf OF
‘saula SNOIHLNYLS JO NOILNIYLSIG
OH. 111] ACANTHODRILUS. 169
tions from that part of the world do not so frequently as
formerly contain new species. This fauna consists prin-
cipally of species of the genus Acanthodrilus. There are
three genera of the same family peculiar to New Zealand,
viz. Octochetus, Plagiocheta and Deinodrilus. All these
worms form a very well-marked family which is character-
ised by the fact that the male sperm ducts open on to the
Xvilith segment of the body, and that on to the two seg-
ments in front of and behind this open a pair of coiled
tubular glands accompanied by a bundle of modified
“penial” setze. The bulk of the species of Acanthodrilide
belong to the genus Acanthodrilus itself. Besides this
genus there are three species of quite a different genus,
Microscolexz. This genus is referable to another family
allied however to the Acanthodrilide. There is here only
one pair of tubular glands which open in common with or
or very close to the sperm ducts upon segment xvi. The
penial sete also exist. The remaining Oligocheta terri-
cole of New Zealand, apart from introduced Lumbricide,
are a few species of Pericheta, or rather a closely allied
genus which I have named Diporocheta. In the more
southern parts of the South American continent precisely
the same families are met with; and not only that, but
the same genera. Dr Michaelsen of Hamburg has recently
made a voyage to that part of the world, and has brought
back with him a very large collection of earthworms;
these belong, with the exception of introduced Lumbricide
and a single Pericheta, exclusively to the genera Micro-
scolex, Acanthodrilus and Kerria (a near ally of Acantho-
drilus). So far as we know at present not a single species
170 . MICROSCOLEX. [CH. IIT
from America is identical with any New Zealand form;
but they are all closely related. This however does not
exhaust the antarctic region. During the voyage of the
“Challenger” and the transit of Venus expedition a few
earthworms were collected at Kerguelen and at Marion
Island. These amounted to only a single species, which
is common to both islands, and is a member of the genus
Acanthodrilus. The same genus also occurs in’ South
Africa; but Africa so far as concerns the family Acantho-
drilide chiefly abounds in the genus Benhamia, which
differs in a few small though constant points from
Acanthodrilus. The genus Benhamia in the opinion of
Dr Michaelsen, is really limited to Africa. Species have
been described from America, the West Indies, and from
India and Malaya; but it is possible, as Dr Michaelsen
thinks, that. they have been imported by man. The
family Acanthodrilide indeed is almost exclusively. ant-
arctic, and in any case by far the majority of its species
and genera are limited to the antarctic area. Microscolex
passes into North America, has been met with in Europe
and the Azores and Canaries, and also occurs in Australia.
But with the exception of America all the species found
outside the antarctic area are identical with species living
within it’; this suggests importation from abroad. This
series of facts is a very remarkable one, and deserves more
consideration than has been devoted to it in forming any
theory about a possible former antarctic continent of greater
dimensions than the present shrunken land mass. The
facts seem also to point to a more recent communication.
1 Excepting M. poultoni from Teneriffe'and M. algeriensis from Algeria.
CH. -111] . PRESH-WATER FISH. 171
between Patagonia and New Zealand than between either
of. these countries and the Cape of Good Hope. These
however are by no means the only facts which seem to
point to some ready method of transit between these
different regions for purely terrestrial or fresh-water
animals. Many writers have with justice emphasised the
extremely significant fact that the fresh-water fish Ga-
laxias attenuatus occurs in Tasmania, New Zealand, the
Falkland Islands and the southern extremity of the South
American continent. This is perhaps the only case of a
species of fish with so wide a range in the antarctic hemi-
sphere; but the two families of Salmonoid fishes Ga-
laxitde and Hoplochitonide are restricted to the same
countries with the addition of southern Australia. A
species of Galawias has recently been ‘described from
India; but Mr Blanford states that the determination is
doubtful. Now a fresh-water fish, even more if possible
than the purely terrestrial Oligochwta, needs a continuity:
of free land surface for its migrations’. And the fishes of
these two families form a considerable proportion of the
entire fish fauna of the countries where they occur. It
is well known, of course, that the ova of many fish, par-
ticularly of Salmonoids, can be safely transferred in ice,
and will hatch out at the other end; rivers in New
Zealand have been stocked in this very way. So that
there is no antecedent improbability in the iceberg theory
of the migration of these fishes. .But in this case it is
1 The possibility however must be borne in mind that they have been
independently evolved from marine ancestors. This can hardly perhaps
apply to Galavias attenuatus, to the same species.
172 FROGS OF AUSTRALIA. [cH. II
remarkable that oceanic islands which happen to be within
the districts visited by icebergs have not also been stocked
with fish. This criticism it will be seen cuts both ways.
We cannot apply it to continents, if we are forbidden to
consider it in connection with oceanic islands. It has
already been pointed out in connection with the same
subject of oceanic islands that they are invariably desti-
tute of frogs or of amphibians of any kind. These crea-
tures are quite powerless to migrate across the sea. Now
a family of frogs, the Cystignathidw, are common to South
Australia and to South America. I do not think it
prudent to lay any particular stress upon the likeness
in the Coleopterous fauna of the antarctic parts of the
world; for beetles or their larve can with comparative
ease be carried about by that convenient deus ex machina,
the floating log; more remarkable is the negative fact
that the land shells do not support the idea of a former
extended antarctic continent. Precisely the same facilities
are enjoyed by the terrestrial mollusca for dispersal as by
msects. It is however difficult to extract anything of
value out of this fact either in favour of or against the
view that the antarctic current had formerly a greater
extent to the northward. It is perhaps to be correlated
with the fact that there is only a single land shell in Ker-
guelen, which would seem to be some indication that in
this quarter of the globe some hindrance exists to the
migration of these animals. The matter must remain
unexplained for the present.
The distribution of the Isopod genus Serolis may be
cited as further evidence in the same direction; by some
CH. III] SPECIES OF SEROLIS. 173
it is made the type of a distinct family of that group, and
it is in many respects peculiar; the outward form recalls
that of the extinct Trilobites—“ An protypon Entomolo-
thi?” asks Fabricius, and attempts to reinstate the genus
in the neighbourhood of those long defunct Arthropods
have lately been made. Apart from this spurious claim
to interest, Serolis has a genuine attractiveness by reason
of its remarkable geographical range. It may be ex-
plained in the first place that Serolis—or the Serolide, if
the family be approved of—differs from all other Isopods
in the facts that (1) the first two segments of the thorax
are more or less completely united with the cephalic
shield, (2) that the last three segments of the abdomen
are fused with the telson, (3) the wide depressed body
with usually elongated epimera. This assemblage of
characteristics divides the Crustaceans in question from
others.
There are in all twenty-six species of the genus, of
which perhaps some (those queried) are a little doubtful.
They are thus distributed :
(1) Off Pernambuco (675 fathoms), Serolis gracilis’.
(2) Off Pernambuco (410 fathoms), Serolis ant-
arctica. The same species also found in 1375
and 1600 fathoms near Crozets.
(3) Off Rio Janeiro in 600 and 2040 fathoms, Serolis
newra.
(4) Off antarctic continent, near New Zealand in
410—1975 fathoms, Serolis bromleyana.
1 For a full account of this genus see Beddard, Report Zool, Chall.
Exp. Vol. x1., and Pfeffer, Jahrb. Hamb. wiss. Anstalt, 1888.
174
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
(15)
(16)
(17)
(18)
(19)
(20)
(21)
(22)
(23)
(24)
SEROLIS OF AUSTRALIA. [cH. ui
Serolis paradoxa, Patagonia, Falkland Islands,
New Zealand (?), Senegal (?)
? Serolis trilobitoides, South Shetlands, Patagonia.
Serolis gaudichaudt, Chili.
Serolis planus, Patagonia.
Serolis convexa, Patagonia.
_Serolis schythet, Patagonia, New Zealand (?).
Serolis septemcarinata, Marion and Prince Ed-
ward Islands, Kerguelen, S. Georgia.
Serolis latifrons, Kerguelen, Crozets, Auckland
Island.
Serolis cornuta, Crozets, Kerguelen.
? Serolis serrei, Patagonia.
? Serolis acutangula, ? locality.
_Serolis pagenstecheri, 8. Georgia.
Serolis polita, S. Georgia.
Serolis carinata, California.
Serolis tuberculata, Bass’ Strait.
Serolis australiensis, Australia.
Serolis elongata, Australia.
Serolis pallida, Australia.
Serolis longicaudata, Australia.
Serolis minuta, Australia.
It will be noted that four are deep sea forms; and we
postpone consideration of these ; for it is well known that
the deep sea fauna must be studied by itself. The
remaining forms are absolutely confined to the antarctic
region and to the south coast of Australia, with the
doubtful exception of Serolis paradoxa and S. carinata.
CH. Ir] DISTRIBUTION OF SEROLIS. 175
They are most prevalent on the coasts of Patagonia. A
few, but very few, species range widely through the
antarctic region; thus S. septemcarinata extends from
S. Georgia to Kerguelen, The Australian species, with
the exception of Serolis minuta, form a well-marked
assemblage to which perhaps a different generic name
ought to have been given; these species differ from the
typical species of the genus in the fact that the dorsal
part of the sixth thoracic segment is absolute in the
middle line; there are also other smaller particulars in
which these Australian species diverge from the normal
structure of the genus.
Here we have a family of curiously restricted range ;
it is exclusively antarctic, not getting so far north as the
equator. It may be surmised that the genus came into
being in the antarctic region; whence conditions of
temperature did not allow it to migrate. But a difficulty
is presented by the wide range within this area of species
which being addicted to shallow water would. find some
hindrances in crossing the thousands of miles of deep
water which part Patagonia from the Crozets. Possibly
this difficulty is removed by the supposition that in former
times the antarctic continent extended further north than
it does now, thus enabling the species to wander far
without altering greatly the surrounding conditions. The
marked differences which distinguish the Australian
species from their more southern allies are so far a proof
of the more remote period at which a migration to the
shores of Australia was possible. A cold current, which
sweeps up the western shores of South America, may
176 MADAGASCAR. [CH. III
have carried with it the single species S. carinata, which
extends to so northerly a situation.
“ Lemuria.”’
By some naturalists, Madagascar is believed to be the
remnant of a great continent extending across the Indian
Ocean, and has been referred toas Lemuria. Some of the
islands lying to the north of Madagascar will be in this
event other scraps of the same continent. Among these
islands the Seychelles at least offer other evidence of
being the last fragment of a vanished continental expanse :
they are a group of about thirty islets lying 700 miles. to
the north of Madagascar. Though oceanic in most of
their characters they are composed of “granitoid or
gneissoid” rocks, thus arguing original continental con-
ditions. In spite of this fact in their geological structure
they do not possess a single indigenous mammalian
inhabitant. This fact, it may be incidentally pointed out,
is of importance; it shows that the true remains of
continents may be without mammals and that the absence
of mammalia is not always to be relied on as an infallible
sign of an oceanic island. Their small size may have
caused the decay of the original mammalian fauna, an
argument that can of course be applied to the doubtful
case of the Galapagos archipelago (see below). There are
however four Amphibia, a more infallible sign of a former
continental connection. These are a frog, Rana mascarina,
which is widely distributed in this region of the world,
a peculiar Tree frog and two Cecilians, that group of
CH, IIT} MASCARENE BIRDS, 177
tailless and underground Amphibia particularly character-
istic of Ceylon. Mr Blanford instances the Seychelles as
the only thoroughly authenticated case of an oceanic
island composed of granitoid rocks. This however only
takes us necessarily as far as a possible former connection
with Madagascar, which Mr Wallace admits, though pre-
mising that if this and the other island groups in the
neighbourhood were ever connected with each other and
with Madagascar “it was probably at a very remote
period.” There now remain the characters of the fauna
of the Mascarene region for consideration. So far as
concerns the Mammals and Birds the evidence is not so
strong, or rather it need hardly be considered as any indi-
cation of a former connection with India.
The mammals, as has been already pointed out, are
either African or altogether peculiar, chiefly the latter.
It is true that there are Oriental birds in Madagascar,
but these are, as Mr Wallace acutely points out, “slightly
modified forms of existing Indian genera or...species
hardly distinguishable from those of India.” This argu-
ment, triumphantly adduced by Dr Hartlaub as evidence
of the former “ Lemuria,” really points precisely the other
way. Apart altogether from the ready means of migration
possessed by birds—birds offer most unreliable evidence
in proving a matter of this kind—we should expect on the
hypothesis of a former land connection with India not to
find such close resemblances; what is wanted to prove
the theory of those who believe in “Lemuria,” and use
birds to support their theory, is to discover Mascarene
birds which though presenting certain likenesses to. those
B. Z. 12
178 AMPHIBIA AND FISHES. (CH. III
of India should be widely different as to species and
genera, showing a great divergence which would have
naturally occurred in the time during which India and
Madagascar have been, on any hypothesis, divided.
If however we turn to other groups of the animal
kingdom, the rejection of the hypothesis of a former
connection between India and Madagascar does not appear
to be so reasonable. For example, the Amphibia are not
to be passed over; there are according to Mr Blanford, 16
species of the genus of frogs Rhacophorus, all the other
species being Oriental. The genus Calophrynus has three
species, of which two are Oriental and one Mascarene.
The family Discophide comprises seven genera and thir-
teen species in Madagascar; the only other member of
the family is Burmese. Among fresh-water fishes Mr
Blanford calls attention to a remarkable instance of an
intermediate form being a native of Madagascar. It is a
peculiar genus, named Paretroplopus, belonging to the
family Chromidide and intermediate between the African
genus Hemichromis and the Oriental genus Ltroplus.
This family of fishes is especially characteristic of Africa,
and is also found in South America. It is rarer in the
Oriental region. The facts that Mr Blanford has laid
stress upon seem to indicate, as he remarks, that there
have been in this family of fishes two lines of migration
from Africa to India. One by way of the Nile into
Palestine, where the family occurs; the other through
Madagascar, leaving behind evidence of its passage in the
shape of the genus referred to which has so to speak not
quite attained to the Asiatic character. The importance
CH. 11] MOLLUSCA OF SEYCHELLES. 179
of the evidence offered by spiders is emphasized by M.
Simon’s removal of Madagascar from the Ethiopian and
its transference to the Oriental region’.
The land and fresh water Mollusca are a doubtful
group with which to have many dealings of the present
kind; they are not so reliable as many, owing to the fact
of their possessing a shell which has made them the
objects of collectors who often do no more than refer to the
“animal” as if it was a casual and unimportant inhabitant
of the shell. But their evidence, so far as it can be read,
is not without bearings upon the problem that we are
now engaged in. A large proportion of the land Mollusca
are peculiar; and there is, as in the West Indies, a great
development of the Cyclostomatide. In this latter family
a genus Cyclotopsis is limited to the Mascarene islands
and to the Indian peninsula. In the Seychelles we have
Cyathopoma and Leptopoma, which are also Oriental
genera, and Helicina, which is almost world-wide but not
African. The two families to which these belong, Cyclo-
phoride and Helicinide, “must apparently,” says Mr
Blanford, “have reached the Seychelles from the eastward,
for not one of them is found in Africa.”
Mr Blanford deals with the obvious suggestion that
the presence of these animals may be recent and due to
floating trees or the like. The currents however indicate
that the transference of such small creatures would be
from the Seychelles to India and not in the reverse
direction. Another possible method of colonisation by
the help of winds is not to be considered ; for it appears
1 Trouessart, La Géographie Zoologique, p. 210.
12—2
180 EARTHWORMS OF MADAGASCAR, [CH. III
that great wind storms, prevalent in this part of the world,
do not cross the equator, which they would certainly have
to do in order to convey animals or their eggs from India
to the Seychelles. The earthworms of Madagascar are
unfortunately not at all well known. But what we do
know supports the facts brought together and emphasized
by Mr Blanford. There is in the island at least one
peculiar genus. This has been termed by Dr Michaelsen
Kynotus, and it contains three or four species. The only
other earthworms known from Madagascar are Perrier’s
Acanthodrilus verticillatus and Pericheta madagasca-
riensis and P. indica. The former worm is only very doubt-
fully an Acanthodrilus; I bring forward reasons in my
forthcoming Monograph of the Oligocheta for referring it
to the already mentioned genus Kynotus, with one of the
already described species of which it may be identical.
Pericheta madagascariensis is closely allied to, if not
identical with Megascolex armatus,a common Indian form.
Pericheta indica is not far from being a cosmopolite.
Now the genus Kynotus belongs to the family Geosco-
licide, which is distributed through tropical South
America and the West Indies, tropical Africa, and certain
parts of Malaya; it just gets into Europe. But the old
world forms can be separated from those of the new world
to so marked an extent that it is permissible to divide the
family into two subfamilies. The spermathece in the old
world forms if present at all, and they are occasionally
absent altogether, are very numerous and minute, while
those of the American genera are the usual paired
structures which are so characteristic of the Oligocheeta.
CH. 11] EARTHWORMS OF MAURITIUS AND RODRIGUEZ. 181
The bulk of the old world genera of Geoscolicide are
Oriental; and it may be fairly said that Kynotus is at
least as nearly allied to them as it is to the African genera.
Another possibly important piece of evidence to be
derived from this group of animals is the existence in the
Seychelles of a species, which I have dissected and cannot
distinguish from the Oriental Megascolex armatus, already
referred to. But this worm, if truly indigenous, indicates
obviously a migration from India. In the Mauritius and
in Rodriguez are species of the characteristically Oriental
genus Pericheta, which are not unfortunately thoroughly
well known anatomically, but in one instance, Pericheta
robusta from Mauritius, are probably distinct species. I
have described Perichewta mauritiana from’ the same
island, which is certainly not identical with any known
and adequately described species. There are thus some
facts to be drawn from this group of animals not
unfavourable to “ Lemuria.”
But the most striking evidence perhaps is geological
and paleontological. This evidence I again abstract from
Mr Blanford’s address to the Geological Society. It
comprises evidence derived from several distinct periods of
the Palzeozoic and Mesozoic epochs, and is therefore not
by any means so “ fragmentary” as has been alleged. It
is pointed out that in carboniferous times there was a
great resemblance between the plant faunas of Australia,
India and South Africa. With this correspondence was a
great difference from the flora of Europe. Supposing this
flora to have been transported across the sea, there would
of course be no use in invoking the presence of what Prof.
182 MADAGASCAR FOSSILS AND “LEMURIA.” [CH. III
Suess terms “Gondwana land” instead of Lemuria, But
if so, why are there no European plants in the same strata
in India, &.? For such plants do occur in the carboni-
ferous strata of certain parts of Africa and Brazil. Nor
do we find this kind of evidence only in carboniferous
times. In the formation known as Cenomanian we have
similar evidence, though in this case derived from marine
organisms and thus serving to check the data derived
from plants. At Nerbudda, in Western India, eight species
of fossil Echinoderms have been found, of which six are
also known from European rocks. But in South India
26 species have been found, of which only four, and two
of these are doubtful, occur in European strata. The
inference obviously is that the Nerbudda fossils are the
remains of animals which lived in a sea continuous with
the sea of the same period in Europe, and that the
Trichinopoly beds are the bottom of a sea which was
separated from the northern sea by-a land barrier. The
Trichinopoly fauna recurs in Natal.
Further evidence of the same kind comes to hand from
a study of the Jurassic fauna of the world. Lastly, the
fossil .Belemnites of Madagascar are not identical with
those of the beds of a corresponding age in Uitenhage, a
fact which may at first sight appear to be hardly worth
bringing forward in support of the present hypothesis. But
the interesting fact about these fossils is that they belong
to forms which are typical dwellers.in warm seas, while the
single Uitenhage Belemnite is as distinctively a cold-water
form, thus tending to prove the existence of a belt of land
shutting off a cold south sea from a warmer equatorial sea.
CHAPTER IV.
THE FAUNA OF ISLANDS.
THE principles dealt with in the preceding Chapter
are also admirably illustrated by the fauna of islands, of
which some account will now be given.
The Fauna of the British Isles.
The islands of Great Britain and Ireland are situated
upon a bank which comes so near the surface that the sea
is nowhere more than comparatively a few fathoms deep.
From the neighbouring coast of France England is se-
parated by barely thirty miles. There can be no doubt
in fact that the separation is, geologically speaking, very
recent, probably within the period of human occupation.
We should expect therefore to find the very closest
similarity in the fauna of England of the adjacent parts
of the Continent; this is precisely what we do find, the
differences being chiefly in the poverty of the British
fauna as compared with that of the Continent.
As Mr Wallace has pointed out, this poverty is
probably to be accounted for by the recent glaciation of
184 PECULIAR BRITISH BIRDS. [cH. IV
these islands, which destroyed a large proportion of the
inhabitants, unable to escape to more southern and warmer
latitudes or, if they did, cut off from returning by the
severance of the land. Poor though the fauna is, there
are still a few species which are really peculiar to these
islands, and are not found, or at least have not as yet
been found, anywhere upon the Continent. As however
many of these supposed peculiar species are obscure and
small insects, it is quite within the bounds of possibility
that they remain to be discovered later upon the Continent,
Among the Vertebrata the peculiar species are mainly
fishes; there are however three species of birds, or at
least forms that are reputed to be species, found nowhere
outside of the British isles; the only one of these however
which is without any question at all a distinct form is the
grouse Lagopus scoticus. The Cole-tit Parus britannicus
is held by some naturalists to be distinct from the Parus
ater of the Continent; and in the same way the
British form of the Long-tailed tit, called Parus rosea, is
distinguished from its ally in Europe. The St Kilda
wren is possibly also to be added to the list of peculiar
species.
Mr Wallace enumerates no less than 15 different kinds
of fresh-water fishes which he states, on the authority of
Dr Giinther, to be well-marked species. They are entirely
Salmonoids and nearly all of them are lake fish; they
include the familiar Guillaroo trout, the Loch Leven trout,
the Gwyniad, the Vendace and the Pollan. Considering
that in many cases these fishes are extremely restricted
in their range within the islands, it is not surprising that .
CH. Iv] PECULIAR BRITISH INSECTS. 185
they do not range beyond. The Welsh Charr for instance,
Salmo perisit, is limited to the Llanberris lakes. Out of
these fifteen fish no less than six are confined to Ireland.
The specialisation of these fish is comparable to that of
the Cassowaries and the Ibexes dealt with on another
page ; they live in isolated areas whose living inhabitants
can never intermingle except by the rarest circumstances,
such as a whirlwind taking up the young fry and depositing
them still alive in an adjacent lake; at any rate the very
fact that they are of different species shows that inter-
communication is not frequent.
The list of peculiar insects is a much longer one; but
some entomologists hold that it is a list which is only at
present imposing upon paper; that in fact the insects
really await discovery upon the Continent. Mr Wallace
however is of opinion that the list of peculiar British
insects is in the main to be depended upon ; he points out
that all islands show an equal if not larger proportion of
peculiar insects than of any other class of animals.
Besides, the climate of this country is different from
that of any part of the Continent, a further reason for
the validity of the argument that there are really peculiar
species restricted to these islands. Of butterflies there
are only two species which are exclusively British; and
both of these are very limited in their range within these
islands; indeed one has become in the last few years
absolutely extinct. This is the “ Large Copper,” Polyom-
matus dispar. Its extinction has been no doubt caused
by the draining of the fens where it was formerly abundant.
The other butterfly is a variety of one of the common
186 MOLLUSCA OF IRELAND. [cH. IV
“Blues” known to entomologists as Lycena agestis; the
variety being termed JL. artaxermes; it occurs upon
Arthur's Seat and upon some of the other Scottish hills.
No less than 87 moths are given in Mr Wallace’s
list as-peculiar to Great Britain. Of these of course the
larger portion are “Microlepidoptera,” and frequently
minute forms, which might be easily overlooked were they
really to occur also on the Continent. Though there are
these 87 moths they do not all of them rank as species.
However 61 are considered to merit specific distinction.
This number is, according to the late Mr Stainton, to be
further reduced to 50 undoubtedly distinct species since
some of the reputed species are rather local forms than
definable species. Of the beetles Mr Wallace’s list shows
72 species and varieties confined to the British islands;
the list of insects concludes with the mention of three
Trichoptera, all apparently good species, which are not
found out of the British isles.
The land and fresh water Mollusca present us with a
few peculiar forms; a black slug spotted with yellow,
Geomalacus maculosus, was discovered on the shores of
lake Carogh in Kerry in the year 1842, and has not been
met with elsewhere since that year. A small pond snail,
Lymnea involuta, is confined to a small Alpine lake near
Killarney; finally there are two small shells which are
ranked as species, one a bivalve, the other an univalve,
besides 79 varieties.
The Rev H. Friend reports’ the presence of a species
of Lumbricus (L. papillosus) in Ireland, which has not yet
1 Trish Naturalist, Feb. 1894.
“SWYOS LONILXA WW
‘'SUNWAT JO NOILNEIYLSIG
CH. Iv] LEMURS. 187
been found elsewhere, and Mr Benham’s! peculiar new
genus Sparganophilus, found in the Thames, is so far as
we know limited to that river. There are one or two
other examples of Oligocheta which have not been met
with outside of the British islands.
There are thus a fair number of animals which are
confined to the British islands; but there are no marked
generic (except the worm Sparganophilus) or family types ;
nor is the proportion of peculiar forms large as compared
with that of the animals which are also found upon the
continent of Europe. But this is perfectly in harmony
with the geological history of these islands, which teaches
us that the severance from the continent of Europe is,
geologically speaking, an event of yesterday.
The Fauna of Madagascar.
Madagascar is a large island about twice the length of
England, and as broad nearly all through as the widest
part of England. It is situated about 250 miles from
Africa. It is largely forest covered; but there are also in
the central granite plateau moors. The fauna is both
rich and peculiar. Among the Mammals the most
characteristic forms are the Lemurs. Of this group of
mammals there are no less than nine genera, viz. Indris,
Propithecus, Avahis, Hapalemur, Lepilemur, Lemur,
Chetrogaleus, Microcebus, and Chiromys, absolutely con-
fined to the island. These genera contain all belonging
to the subfamilies Chiromyide, Lemurine, and Propi-
1 Quart. Journ. Micr, Sci. Vol. xxxiv.
188 RODENTS OF MADAGASCAR. [cH. IV
thecine; the remaining Lemurs consist also of three
subfamilies, which however include but few genera and
species, and are distributed in Africa and in the Oriental
region. Doubtless, as Mr Lydekker has pointed out in
the “Royal Natural History,” the excessive allowance of
Lemurs is partly to be attributed to the entire absence of
large and powerful carnivorous animals. Carnivora are
not at all abundant. But they include two highly
peculiar forms. Firstly, Cryptoprocta, a Viverrine believed
by some to have relations with the extinct Creodonta but
which is at any rate to be referred to a separate subfamily
of the Ailuroidea, and Hupleres, which is also an isolated
form and has some affinities to the Insectivora. This
latter group includes five genera of a peculiar family, the
Centetide, found nowhere else in the world except in
certain islands of the West Indies!; the Rodents, an
universally distributed family of mammals, all belong to
the Myomorpha (the rat tribe); but they are all peculiar
genera of that group, viz. Nesomys, Hallomys, Hypogeomys
and Brachytarsomys. The ungulates are exceedingly
poorly represented; there is only a Potamochwrus (P.
edwards), and quite recently a Hippopotamus has been
dug up from marshes where its bones were commingled
with those of other living and recently extinct forms. Mr
Blanford’ reckons that out of the twenty-four genera of
mammals of Madagascar only two, Potamocherus and the
shrew Crocidura, exist in Africa.
1 Mr Dobson however (Ann. and Mag. Nat. Hist. Sept. 1884) denies
that the W. Indian Solenodon is a member of this family.
2 Presidential address to Geol. Soc. 1890.
CH. IV] MESITES AND LEPTOSOMA. 189
The birds are not so strikingly peculiar as are the
mammals; still there are not a few genera and species which
are restricted to Madagascar. Among these is the re-
markable Mesites, which is believed to be allied to the
Sunbittern of tropical America and to- the Kagu of New
Caledonia, and is possibly to be regarded as a relic of a
primitive group of rail-like birds once dominant in all
parts of the world. Leptosoma is also a peculiar bird,
whose affinities are far from clear. The late Mr W.
A. Forbes’ thought from his investigations into its
structure that it might be regarded as the type of a
distinct family near to the Rollers (Coraciide). The
Cuckoo genus Coua is also peculiar to the island, as are
also the Vasa parrot; Coracopsis, and a few more types. On
the whole the avian fauna is not so remarkable as the
mammalian; but in both cases the fauna of Madagascar
stands out as noteworthy by the absence of animals which
might be expected to occur just as much as by reason of
the peculiar types which do occur. There is an entire
absence of the characteristic African Elephants, Rhino-
ceroses, Anthropoid Apes, Lions, Hyznas, &c. and among
birds, of Hornbills, Plaftaineaters, and Colies.
The reptiles are almost as peculiar as the mammals.
The chief feature of the island is the presence of the
American genera Philodryas and Heterodon among snakes,
a fact which is remarkably paralleled by the Centetide
among the Insectivora. There is an exactly analogous
case among lizards; for two genera, Hoplurus, Chalarodon,
1 P. Z, S. 1880.
190 FERNANDO NORONBA. [CH. IV
are Iguanoids—a family otherwise restricted to America.
The Chameleons are very abundant in Madagascar, more
so than in any other part of the world, though they are by
no means limited to the island. As with mammals and
birds the reptiles which are remarkable for their absence
are as numerous as those which are noteworthy for their
presence. The most striking example is perhaps the
large group of Monitor Lizards, which abound not only in
Africa but in many parts of the old world, to which
division of the globe they are confined. Some further
facts about the zoology of Madagascar will be found on
page 176 et seq., apropos of its relations to India.
The Fauna of Fernando Noronha.
The island of Fernando Noronha lies at a distance of
194 miles N.-E. from Cape San Roque on the coast of
Brazil. -It consists now of an archipelago of small islands;
but the original discoverer, Amerigo Vespucci, speaks of
it as one island; it seems probable therefore that the
splitting up into an archipelago has occurred within the
last 400 years. The recent formation of an archipelago is
also rendered probable by the fact that the individual
islets have not their peculiar inhabitants, but that—in the
words of Mr Ridley*, whose report upon its zoology has
furnished me with the material for the present section—
“almost all the species noted occur on all the islands
suitable for their existence.” This is entirely different to
the older oceanic archipelagos, such as the Sandwich
1 Trans. Linn. Soc. 1886,
CH, IV] FAUNA OF FERNANDO NORONHA. 191
Islands (see below). The fauna is poor. No indigenous
mammal is to be found, with the possible exception of a
mysterious rat belonging to a tribe which Vespucci
describes as “Mures quam maximi.” This description
seems inapplicable to the black rat, which is now found in
company with the common mouse. The cat also is said
to have become feral, but there is not the slightest
ground for believing in a truly indigenous cat. There
appear to be only three land birds, of which two are
peculiar; the peculiar species are Vireo gracilirostris and
Elainea ridleyana, both very nearly related to American
forms. The third bird is a dove, Zenaida maculata,
“merely a small race of the ordinary Z. maculata of the
South American continent.” It is not, however, pecu-
liar even as a small race, to the islands; for precisely
the same variation occurs in Brazil.
Only three reptiles exist in Fernando Noronha.
These are an Amphisbena (A. ridleyi) peculiar, a skink
(Mabuia punctata) from Demerara, and a common Gecko.
The peculiar species has its nearest ally in the West
Indies, not on the mainland of South America.
The fresh-water Mollusca consist of a species of
Planorbis peculiar to the islands. The land Mollusca are
seven in number; of these four are peculiar, but only as
species, not as genera. A peculiar Centipede is described
by Mr Pocock under the name of Geophilus ridley, whose
nearest ally occurs at San Francisco. There is also a
peculiar Millipede, Spirobolus noronhensis. Two species
already known were also met with. Among the Insects
are two peculiar genera, and a considerable number of
192 AFFINITIES OF FAUNA. [cH. IV
peculiar species. In all 75 species of Insecta were
identified, and out of these 27 were peculiar species,
including the two genera above referred to. The fresh
waters of the islands contained, besides the Planorbis
mentioned, an Ostracod and a Gammarus, both believed
to be peculiar. There was a total lack of fresh-water
fish and of fresh-water as well as terrestrial Amphibia.
One earthworm is known from Fernando Noronha,
identified by Mr Benham with the widely ranging but
especially Neotropical Pontoscolex corethrurus.
The most salient features therefore in the fauna of
these islands are the total want of mammals of an
indigenous character, of fresh-water fish, and of Am-
phibians, the rarity of reptiles, and finally the large
number, speaking relatively to the total of course, of
indigenous forms peculiar to the island. Of these how-
ever but few are of new generic types; but this statement
as in the case of the fauna of Kerguelen, to be dealt
with presently, must be tempered by reflection as to the
different ideas which different naturalists have of the
value of a genus. As to the affinities of the fauna it is
noteworthy that the West Indies enters largely into the
matter; there is not, as might be assumed at first, an
absolute likeness with the nearest coasts of South America.
But the winged fauna, Mr Ridley points out, whether
they are endemic or have a wider distribution, have a
South American facies which is quite unmistakable.
CH. IV] BIRDS OF KERGUELEN. 193
The Fauna of Kerguelen.
The island of Kerguelen is situated in the southern
ocean in lat. 50, about half way between Australia and
the Cape of Good Hope. It is a large island of irregularly
indented form measuring in greatest diameter some 80
miles. The island is moreover situated on a plateau
which extends for a distance of more than 150 miles.
The island is entirely built-up of volcanic rocks; it is
chiefly formed of basalt; but trachyte and phonolite enter
also into its composition.
Our information as to the fauna of Kerguelen is
apparently fairly complete. It was investigated by an
English expedition some years ago, the results of whose
discoveries were published by the Royal Society in 1875.
Later the “Challenger” stayed for some time at various
parts of the coast, and the German ship “ Gazelle” during
its voyage in the years 1874—76 touched at the island
and collected a quantity of material.
In spite of the large size of the island, there is no
indigenous. mammal; the only mammal indeed which
occurs there, apart of course from marine forms, is the
ubiquitous Mus musculus. As the island is visited by
whale fishermen it is easy to understand how the common
mouse may have been introduced in ships. The only
land bird is the duck, Querquedula eatoni, a species
peculiar to this island and to the not very remote Crozets ;
the bird lives in marshes. Of the marine birds Sterna
virgata is also peculiar:-to Kerguelen and to the Crozets.
B. Z. , 13
194, INSECTS OF KERGUELEN. [cH. Iv
Only a single species of land shell has been so far
discovered ; this is Patula hookeri, a species closely allied
to Helix diane of S. Helena, to H. quadrata of Juan
Fernandez and to H. tessellata.
Among insects there are on the other hand several
peculiar forms. The beetles are in every case without the
second pair of wings; they comprise Hctemnorhinus viridis
and a few other species of that genus, Phytosus atriceps
and Cannonopsis. A moth with rudimentary wings has
been recorded, as well as the peculiar genus (peculiar to
the island) Embryonopsis halticella. The Diptera do not
show the same rudimentary character of the wings that is
met with among the Coleoptera; there are however six
peculiar genera with a species apiece and an introduced
form.
The spiders of the island are represented by two
peculiar genera, Myro and Pecilophycis, of which the
latter is so aberrant that the Rev. O. Pickard-Cambridge
has felt it necessary to form an entirely new family for its
reception. Among the fresh-water invertebrates, which
are not very numerous, there are no peculiar genera; but
all the species are, so far as we know at present, peculiar ;
these comprise species of the two Crustacean groups
Cladocera and Copepoda, and an Enchytreeid (unidenti-
fied). One terrestrial Annelid has been found and
described by Lankester as an Acanthodrilus (A. kergue-
lenensis); this.is a species peculiar to the island, unless
the Acanthodrilus of the Crozets be the same; but the
1 Phil. Trans, Vol, 168, Extra Volume.
CH. IV] KERGUELEN AND THE GALAPAGOS. 195
genus is widely spread in the antarctic region of the
globe},
There are five striking points about the fauna of
Kerguelen which may be emphasised. In the first place
of course, the poverty of the fauna. Secondly, the immense
number (relatively speaking) of peculiar genera; thirdly,
the fact that there is only one terrestrial species (exclud-
ing birds) which is not peculiar to the island; and fourthly,
that the fresh-water species are not so peculiar as the
purely terrestrial The fact that the Coleoptera are
without the second pair of wings—the pair which are
used for flying in the normal Coleoptera—and that there
is a moth with rudimentary wings, completes the more
remarkable facts which characterise the indigenous in-
habitants of Kerguelen.
The Fauna of the Galapagos.
The Galapagos are a group of sixteen islands, five
larger and eleven small islands—situated to the west of
the South American continent, about 600 miles from the
coast of Ecuador. They have been explored more than
once with a view to their fauna. The most recent account
of them is from the pen of Dr Baur’, who made a careful
study of the entire fauna.
As is the case with Kerguelen, the rocks of which the
Galapagos are built up are entirely volcanic; they consist
of basaltic rocks, masses of scoriz, and lavas; but there
1 See p, 60. 2 American Naturalist, 1892.
138—2
196 REPTILES OF THE GALAPAGOS. [cH. IV
are also, on Charles Island, remains of older volcanic
formations, which recur in one or two of the smaller
islands. All the islands of the archipelago are placed
within the 1000 fathom line. They were first discovered
in the sixteenth century.
Mammalian life is not entirely wanting, but it is
scarce, in these islands. At present we are only acquaint-
ed with two species; one of these is a mouse belonging
to the American genus Hesperomys, which may or may
not be indigenous. The other mammal is a bat; but our
knowledge is here not accurate; for the bat has been only
seen and not collected.
There are on the other hand a good many reptiles.
The most famous are of course the huge tortoises, which
have given their name to the archipelago; there is no
doubt that these bulky creatures, which sometimes reach
a weight of 700 pounds, are truly indigenous; for they
were seen by the Spaniards who discovered the islands.
The peculiar thing about these tortoises is that different
islands are characterised by different species. There are
in all six species of these Chelonians, but the exact
locality of one or two is not known.
Tortoises however are not the only reptiles which live
in or round these islands. Four genera of Lizards exist
there; these are Tropidurus, Conolophus, Amblyrhynchus,
and the Gecko Phyllodactylus.
Of the genus Tropidurus there are altogether eight
species on the islands, each island as in the case of the
tortoises having its own peculiar form. Amblyrhynchus is
a marine genus feeding on seaweeds; it is like the last a
CH. Iv] BIRDS OF THE GALAPAGOS. 197
member of the Iguanide, a family of lizards just not
absolutely confined to the New World. Dr Baur thinks
that when the species of Amblyrhynchus come to be
examined critically, differences will be found like those
between the tortoises of the different islands. There are
three geckos on the islands, all belonging to the genus
Phyllodactylus, already mentioned. These are P. galapa-
goensis, P. leet, and P. tuberculosus; the last lizard is the
only species found on the islands which is not peculiar to
them. In addition to these lizards there are two snakes;
they are both very closely allied to South American
forms.
The land birds, according to Mr Salvin’s paper upon
the subject}, are in all 31 species. Of these only one,
the Rice bird, is not peculiar to the islands. As Mr
Wallace has pointed out there is every possible transition
between this case and birds which are so different from
any found upon the adjacent mainland that they are not
merely of different genera, but of very dubious affinities.
The birds belong altogether to fourteen genera, of which
four are peculiar to the Galapagos; these peculiar genera
are Certhidea, one of the Sugar birds (Ceerebide), Geospiza,
Cactornis and Camarhynchus, all of them Fringillide.
The birds that are merely of different species are all allied
to South American or West Indian forms, or of course to
forms which like Striz flammea (the common Barn Owl)
are of universal range.
As with the reptiles certain of the peculiar birds are
confined to a single island; the same genus has one
1 Trans. Zool. Soc. 1875,
198 INSECTS OF THE GALAPAGOS. (CH. IV
species in one island and one in another. Thus Mimus
parvulus is only met with in Albemarle Island and Mimus
trifasciatus only in Charles Island.
The insects of these islands are not very numerous.
Mr Wallace following Mr Waterhouse allows about
35 species of Beetles, belonging to 29 genera. The
species are as a rule peculiar and so are the gerera in
some cases. But as they are “mostly small and obscure
insects,” it is difficult to be positive upon either of these
points.
The Orthoptera of the Galapagos are equally interest-
ing. Considering that nine different expeditions have been
made to these islands, from which insects of this group
have been brought back to Europe or America, and
reported upon, it may be fairly assumed that our know-
ledge of the fauna is not too incomplete to permit of
conclusions. There are in all 20 species, of which Dr
Scudder, the latest writer on the subject’) leaves with
justice five out of consideration, as they are world-wide
forms and probably not endemic. The remaining 15
include five distinct generic types; but the whole assem-
blage presents, according to Dr Scudder, a South and
Central American facies. Another matter worthy of
mention is the very great prevalence of apterous or
sub-apterous species. The 20 species are in many cases
confined to one of the islands of the Galapagian archi-
pelago. This is so with no less than eleven of them. A
few are found in two or three of the islands; one species
_—Schistocerca melanocerca—is unique for its wide dis-
1 Bull. Mus. Comp. Zool. Harvard, 1894.
CH. IV] PHYSICAL FEATURES OF NEW ZEALAND. 199
tribution in the archipelago; it occurs in no less than
eight islands. The specimens were submitted to a rigid
scrutiny to discover whether they could be referred to
distinct races, but the most that can be said apparently is
that “there is a distinct tendency toward the formation of
races.” On the other hand another species of the same
genus—S. literosa—which occurs in three islands, can be
separated into as many races.
The Fauna of New Zealand.
The fauna of New Zealand has been so abundantly
investigated through the labours of Capt. Hutton and
others, that it is one of the best known quarters of the
globe.
It will\be well to preface our account of this fauna by
a brief skétch of the physical features of the island and
the surrounding ocean. The name New Zealand is
applied to two principal islands which are together
“about as large as the kingdom of Italy.” Their climate
is mild and equable, while the vegetation is luxuriant and
there are no deserts such as occur in Australia. The two
islands lie upon an extensive plateau, where the water is
not more than 1000 fathoms deep; a prolongation of this
submarine plateau runs out and joins New Caledonia to
the north, whence it is continued on to the Australian
continent ; another spur runs out so as to embrace Lord
Howe Island;, elsewhere a depth of over 2000 fathoms
divides New Zealand from Australia. Its distance from
Australia is about 1200 miles, The geological structure
200 BIRDS OF NEW ZEALAND. [CH. Iv!
of the islands shows deposits of ancient sedimentary rocks,
besides jurassic, cretaceous, and tertiary strata; it is t
evidently a continental island, though it exhibits mach
voleanic material of ancient as well as of more modern
date.
The fauna of New Zealand is highly remarkable :
though the island is of the continental type there are
hardly any mammals, no large mammals at all; EE two
bats and a rat—the latter being almost certainly an im-
portation—are known to exist in New Zealand. Rumours
of a larger and, conjecturally, a carnivorous mammal have
been from time to time floated; but the domestié cat may
be responsible for the footprints, assigned to a new and
isolated type of New Zealand mammal, The bats however
are not of universally distributed species; oneiof them is
an Australian form, Scotophilus tuberculatus; the other is
a peculiar genus, Mystacina tuberculata. The birds are
very characteristic; the most salient type is of course the
but recently extinct Dinornis and its allies; there were
until well within the historic period a large number of
species of Dinornithide. The existence or at any rate
the abundance of these often huge birds is ascribed to the
absence of mammals—of carnivorous mammals that is to
say. The curious genus Apteryx is found in New Zealand
and nowhere else; of this genus there are about four
species. It is regarded by Fiirbringer as allied to the
Rails, but to be a low stock of the Ralline birds, a little
more modified however than the Cassowai ies, Emus and
the rest of the so-called Struthious birds; the Apteryges
are placed by the same author in close proximity to the
CH. IV] BIRDS AND REPTILES OF NEW ZEALAND. 201
Dinornithide. It is not only these archaic forms of birds
which are peculiar to New Zealand. Nor are they the
only flightless birds that inhabit: this country. The
parrot, Stringops, an undoubtedly ancient form of parrot,
is a very characteristic inhabitant; so too are the rails,
Ocydromus and Notornis; all these birds, though with
wings better developed than those of the Apteryx, or
Dinornis, are practically without the power of flight.
The “Parson-bird,” Prosthemadera, is another peculiar
form. Mr W. A. Forbes has described’ as peculiar
Mesomyodian genera of Passerine birds, the genera Xent-
cus and Acanthisitta. He regards them as worthy of
inclusion in a separate family, to which the name Xent-
cide is applied; the only other family of Mesomyodian
Passeres that enters the Australian region is that of the
Pittide. The Xenicide are also allied to the Tyrannide
and to the Cotingide of the New World. Another re-
markable Passerine of New Zealand is Heteralocha, which,
like the equally restricted Calleas and Creadion, is
referable to the family Sturnide. Among reptiles the
isolated Hatterta is the most remarkable; the Amphibia
are represented by a single frog, Liopelma hochstetteri
allied to European forms belonging in fact to the Pale-
arctic family Discoglosside. It is curious that there are
. no scorpions in New Zealand ®, since that family exists in
* Australia. The earthworms of this part of the world are
mainly Acanthodrilide, including three genera confined to
1 Pp, Z, S. 1882.
2 Pocock, On the Geographical Distribution of Scorpions. Natural
Science, 1894.
202 EXTINCT BIRDS OF NEW ZEALAND. (cH. IV
New Zealand. The characteristic Australian types are
either absent or but feebly represented. The South
American genus Microscolex is represented by six distinct
species.
In Mr Lydekker’s recently issued “Catalogue of the
Fossil Birds” in the British Museum is an exhaustive list
of the extinct flightless or wingless birds of New Zealand,
which were wonderfully numerous; they may be fairly
considered as part of the existing fauna of the island,
since they have been in existence there up to the historic
period, or disappeared from the island at a period only
just antecedent to it. A new genus, Pseudapteryx, with
but a single species, represents a bird hardly different
from Apteryx and of about the size of the comparatively
small Apteryx owent. Of Dinornis itself no less than four
species are allowed, many of those formerly referred to
the genus being now better placed in closely related but
different genera. These are Megalapteryx, Anomalopteryz,
Emeus, Pachyornis, with at any rate 17 species between
them. Another very remarkable and characteristic inhabi-
tant of New Zealand is the large goose, Cnemiornis, which
is regarded as a near relative of the Australian Cereopsis ;
it was a bird with apparently no powers of flight, for the
keel of the sternum, as in the Struthious birds, is aborted.
The bird was considerably larger than the existing
Cereopsis. There is one certainly known species of the
genus, Cnemiorms calcitrans, and one doubtful one, to
which Mr Lydekker does not give a name. A large rail,
Aptornis, is another inhabitant of New Zealand whose
remains, belonging to two species, are found associated
CH. Iv] FAUNA OF SANDWICH ISLANDS. 203
with those of the Dinornis. Though these great birds
must have led a comparatively unharassed life in New
Zealand before the advent of the Maories, who are
probably chiefly responsible for their disappearance, there
were in the islands at the same time great birds of prey,
which might have proved able to destroy the largest
of Dinornithide. These were birds now referred to the
genus Harpagormis, half again as large as the Golden
Eagle. They are believed to be most nearly allied to the
genus Aquila, but by some are placed rather in the
neighbourhood of the Kites or Falcons. As all the last
mentioned birds come very near to each other, the
affinities of the Harpagornis may be considered to be well
known.
Fauna of the Sandwich Islands.
Our information about this group of islands is growing
rapidly. The second edition of Mr Wallace’s Island
Infe contains a great deal more information than the
first edition; and since that book was published a
Committee appointed to take steps for the exploration
of the islands have reported briefly to the British Asso-
ciation’. The islands in question are a group of largish
islands, 2,350 miles from the coast of America and purely
volcanic in structure. They have of course no indigenous
mammals; there is a reptile or two; but the birds are the
most remarkable and interesting. Dr Sharp states that
out of 78 birds found in the islands 57 are peculiar.
Seven or eight of the twelve or fourteen peculiar genera
1 Rep. Brit. Assoc., 1893, p. 783.
204 BIRDS OF SANDWICH ISLANDS. [CH. IV
belong to a family Drepanidide, which is absolutely
confined to these islands and which may have, thinks
Mr Wallace, affinities on the one hand to the Oriental
Dicceide and on the other to the characteristic American
family of Vireonide, or Greenlet. The Passerine birds of
the islands are the most interesting, for two reasons; firstly
they comprise nearly all the peculiar genera of the islands,
and secondly they show a remarkable specialisation among
the islands. The genus Lowops, for example, of the Dre-
panidide has a different species in each of the islands
Hawai, Molokai and Mani’. This specialisation into pecu-
liar genera, and species with so restricted a range, is of
course correlated with the immense distance to be traversed
and the feeble flight of these birds when compared with
‘that of say the ducks and geese. There are however pecu-
liar genera among the non-Passerine birds, as the little
flightless Rail Pennula ecaudata. Among other peculiar
birds are the Sandwich Island goose, Bernicla sandvicensis,
and a peculiar Buzzard, Buteo solitarius. Of land and
fresh-water Mollusca Dr Sharp states that there are 475
species, all of them peculiar. Out of 1000 insects 700 are
peculiar; but Dr Sharp thinks that the numbers are very
much less than the total will ultimately prove.
General Observations upon the Fauna of Islands.
We have now dealt at some length with the fauna of
six islands or groups of islands, A consideration of the
1 Wilson, Aves Hawaiensis, and Rothschild, The Avifauna of Laysan,
CH. IV] COMPARISON OF ISLANDS. 205
facts brought forward will at once serve to divide these
islands into at least two groups, which are again capable
of subdivision.
Continental Islands.
In the first category are Great Britain and Madagas-
car, which have a copious indigenous fauna of mammalia
and amphibia; to the second category belong the other
islands, which have either no mammalia at all or they are
extremely few, at most one or two species identical with
those found upon the adjacent mainland, and which are
absolutely destitute of amphibia of any kind.
These distributional facts go hand in hand with Geo-
logical structure. Great Britain and Madagascar are
detached portions of continents, which have been sepa-
rated from the mainland for varying periods. The re-
maining islands, with the possible exception of the
Galapagos, which will be considered later, are not such
fragments but have arisen de novo.in the ocean by
volcanic agency. They have never had any connection.
with any continent. The relation between the geo-
logical structure and the nature of the inhabitants is a
real one; the mammalia, as has been already observed,
are not capable of extended migration over the sea on
their own account; it could only be but rarely that a
mammal could reach a distant and oceanic island; and it
would be necessary in many cases that two individuals at
least should emigrate within a reasonable time of each
other. The immense tract of ocean which separates
Kerguelen from the nearest continent has proved an
206 GREAT BRITAIN AND MADAGASCAR. [cH. IV
impassable barrier to mammalian life; for the common
mouse, which, as has been said, occurs there, could easily
be, and doubtless has been, conveyed there by man’s
agency. With the Amphibia the difficulties are even
greater; for in their case there is not only the diffi-
culty of transport, but the serious additional difficulty
that sea-water is fatal to them. It might be urged that
as some of these purely oceanic islands are of large
dimensions and have probably been larger, mammalian
life might have come into existence upon them independ-
ently. This assumption however would be entirely
contrary to our ideas of evolution; indeed it is not
necessary to argue from any a priori point of view, for we
are confronted with the fact that some oceanic islands at
any rate—e.g. S. Helena—are not incapable of supporting
mammalian life, for imported animals do well, and yet
they are totally without an indigenous fauna of the kind.
On the other hand, there is no doubt at all that both
Great Britain and Madagascar are severed portions of
continents, which were amply stocked with mammalian
life when they were finally cut adrift.
Although there is this general similarity between the
two islands just mentioned, it is clear that there are also
differences, and considerable differences too. The mam-
malian fauna of Great Britain, and for the matter of that
the fauna in general, is poor in peculiar forms, restricted
to the archipelago and not found living in the continent
of Europe; there are a good many peculiar species, it
is true, but very few in comparison to the fauna as a
whole.
CH. IV] KERGUELEN AND FERNANDO NORONHA. 207
On the other hand, Madagascar abounds in peculiar
forms, even of family rank, and certainly in numerous
cases of generic rank. This difference again is correlated
with physical conditions. Britain is separated from
France by scarcely 30 miles of sea, which is so shallow
that, as is stated, the dome of S. Paul’s Cathedral in
London, if submerged anywhere in that sea, would stand
for the most part clear above the waves. On the other
hand Madagascar lies 250 miles from the African coast,
from which it is separated by an ocean varying in depth
from 1,000 to 1,500 fathoms. The inference is that the
separation between Britain and Europe is of much later
date than that between Madagascar and Africa. More
time would in all probability elapse between the scooping
out of the deep channel which divides Madagascar from
Africa, than of the narrow and shallow Straits of Dover.
Oceanic Islands.
The four oceanic islands again possess faunas which are
not absolutely the same in character. Fernando Noronha
and Kerguelen contrast with the Galapagos and the
Sandwich Islands by reason of the poverty of their fauna.
They differ from each other also. Kerguelen has a poor
fauna, hardly if at all richer than that which populates
Fernando Noronha, but the number of peculiar types is
larger and more marked; more marked because the types
are to a considerable extent of peculiar genera. This would
tend to prove that Kerguelen is older as an island than is
Fernando Noronha; more time has elapsed since it was
208 THE GALAPAGOS. (cH. IV
originally populated, and during that time the descendants
of the original migrants have had time to pursue an
independent line of development. That Kerguelen is an
island of some antiquity is shown by the submerged bank
which surrounds it, which would have demanded time for
its submergence, and by the occurrence of stratified,
though originally volcanically produced, rocks. We now
come to the remarkable case of the Galapagos. Reptiles
are often not totally wanting in islands of purely oceanic
type; there seems to be some method, at present mys-
terious, in which reptiles have the advantage over
mammals in traversing the sea. So that the actual
presence of lizards and snakes, though they are rather
numerous, is not an absolute bar to regarding the
Galapagos as of purely oceanic origin. The great tortoises
seem to be a huge difficulty; there is no way of slipping
out of the problem by bringing in the help of settlers;
besides, in another island, Aldabra, there are also huge
tortoises. This island belongs to the Comoro group lying
at some distance from Madagascar but connected with it
by a shallow of about 1,000 fathoms in depth. There is
much the same relation between Aldabra and Madagascar
that there is between the Galapagos and the South
American continent. But in neither case could these
huge tortoises, sometimes weighing 700 pounds, have
swum across a wide and deep ocean. And the fact that
the first visitors to the Galapagos mention them shows
that they have not been introduced by man.
Dr Baur thinks that these tortoises are of themselves
almost sufficient to prove the former connection of the
CH, IV] ORIGIN OF GALAPAGOS. 209
Galapagos with the mainland. A further argument in
the same direction is offered by the fact that the fauna of
the mountain peaks of the Galapagos at a height of 900
feet are like that of the mainland at 9000 feet. Given a
great depression this would be accounted for. That view
of the matter clears up in a satisfactory way the difficulty
of the tortoises; it would be inferred from this way of
looking at the problem that the huge Chelonians of the
Galapagos like those of Aldabra had been able to hold
their own by isolation and consequent freedom from
competition or persecution. Mr Wallace however is of
opinion that this assumption is unnecessary. ‘“Con-
sidering the well-known tenacity of life of these animals,”
he remarks, “and the large number of allied forms which
have aquatic or subaquatic habits, it is not a very
extravagant supposition that some ancestral form carried
out to sea by a flood was once or twice safely drifted as
far as the Galapagos, and thus originated the races which
now inhabit them.” The almost total disappearance of
mammals requires explanation on the hypothesis that the
Galapagos are a disjointed piece of South America.
The study of the distribution of animals thus throws an
important light upon geological problems, and tends to
support the belief that animal life has come into being
upon large continental tracts and that it is liable to
variation when isolation is brought to bear. A careful
comparison of island fauna moreover enables some esti-
mate, chiefly of course comparative, to be made concerning
the age of the island in question.
B. Z, 14
210 NEW ZEALAND. [cH. IV
Anomalous islands.
New Zealand is spoken of by Mr Wallace with justice
as an “anomalous” island. Though continental it has
many of the characters of an oceanic island which has
never had any connection with a continent. It contrasts
in the most marked way with Madagascar. Unless the
mysterious carnivore already referred to really turns out
to be what has been suggested, a kind of otter, New
Zealand possesses no indigenous mammals except the
flying bats, which are largely uninfluenced by the ordinary
barriers to mammalian dispersal. The “Maori rat” may
be slightly different from the Mus rattus; but the
difference, if present, is not considerable. On the other
hand there is one frog, and frogs are absent from truly
oceanic islands. Most remarkable are the birds of New
Zealand and the unique Hatteria, the representative of
an otherwise extinct group of Saurians. The fact that
the majority of the birds are flightless is due perhaps
to the absence of destructive mammalia; this flightless-
ness applies not only to the Apterya and the Dinorni-
thidee, but in a lesser degree to the but recently extinct
Cnemiornis and to the Rails. The islands are perhaps
too large to permit of a comparison between this in-
capacity for flight on the part of the birds of New
Zealand and the defective wings of the Coleoptera of
oceanic islands generally. Before considering the bear-
ings of these facts upon former land connections, if any,
between New Zealand and the most adjacent regions, it is
convenient to refer to an ingenious suggestion on’ the
CH. Iv] CASSOWARIES AND MOAS. 211
part of Captain Hutton as explanatory of the Moas of
New Zealand. These recently vanished birds are re-
presented by a large number of different species which
are now placed in more than one genus. The area upon
which they lived is small, and accordingly the number of
species is rather remarkable. In the Australian region
there are nearly as many Cassowaries as there are Moas.
Now these Cassowaries are spread over a considerable
number of islands; they are not limited to the con-
tinent of Australia but occur also in Ceram, New
Britain, New Ireland, &c. On these various islands and
continent are different species. This suggests that
isolation and the absence of opportunity for retaining the
type by crossing with the parent stock was responsible
for the great variety of Cassowaries. If New Zealand
had been at one time a mass of not very distantly
separated islands, each inhabited by its own particular
species of Moa, a state of affairs very like that now
existing among the islands lying to the north of Australia
would result; this is precisely what Mr Hutton in effect
suggests. Mr Wallace regards the suggestion as a rea-
sonable one, and it is impossible to follow a better opinion.
If there has been this oscillation of New Zealand, whereby
a continent (comparatively speaking) has been broken up
into an archipelago, and reconstructed into a continent
again, it may be that we have a clue to the existence of
the large, clumsy, and flightless birds such as the
Cnemiornis and the Notornis. Their case might well be
analogous to that of the Galapagan and Aldabran tort-
oises; or perhaps also to that of the flightless beetles of
14—2
212 RELATIONS OF AUSTRALIA AND NEW ZEALAND. [CH.IV
the Azores, At the same time if the tract of land,
now known as New Zealand, were a mass of smallish
islands during the time that mammalian life came into
existence upon the Australian continent, the small
superficies of the individual islands might hinder the
successful immigration of the primitive mammalia; to get
a successful footing would be in every way more likely
upon a larger than upon a smaller land surface. The
ehances of landing too would obviously be greater in
proportion to the extent of coast line. Had New Zealand
been as Madagascar undoubtedly was, a broken-off frag-
ment of a formerly more extensive Australian continent,
there would surely be some traces of at least marsupial
life. On the other hand it might be well urged in reply
to this that the connection of the two countries may have
antedated the advent of marsupials. A separation may
have occurred while Australia was only populated by the
lower vertebrates. Or with equal probability it might be
pointed out that Australia was joined with New Zealand
when it was itself divided into two halves, of which the
western had only just received its stock of marsupials.
This latter is Mr Wallace’s view. There is no doubt that
the fauna of New Zealand is one of the greatest puzzles
that distribution has to offer.
Some peculiarities of island animals.
Having already dealt with peculiarities of island faunas
as regards the classes of animals which inhabit them, the
absence of some kinds of animals and the presence of
CH. Iv] FLIGHTLESS BIRDS OF ISLANDS. 213
others, there remains another series of facts of which a
brief epitome may be useful. It has been already pointed
out incidentally that many islands, whether oceanic or
not, are, or were until well within the historic period,
inhabited by birds not only of large size but also without
the power of flight, either owing to the partial abortion
of the wing muscles and bones or simply by use, like
the Weka rail of New Zealand. This is quite a common
characteristic of the birds of islands. The Dinornis of
New Zealand, the Dodo of Mauritius, the “Solitaire” of
Rodriguez, are instances to the point. It seems highly
probable that this large size coupled with an incapacity
for flight was correlated with the absence or at least the
rarity of fierce enemies; mammalia are, if not absent,
small in those islands where these large and flightless
birds exist or existed. It is to be observed that even
among the Struthious birds, all of which are flightless, the
majority of the species are inhabitants of islands. This
majority is mainly formed it is true by the genera of
Dinornithide; but a large number of Cassowaries are-
exclusively island forms.
Birds are not the only animals which grow to a large
size upon islands. On a former page attention was called
to the huge tortoises of the Galapagos. These tortoises
are not altered apparently in any other respect; they do
not for instance show any structural feature which could
be said to be analogous to the flightlessness of so many of
the ornithic inhabitants of islands. But the tortoises of
the islands are actually the largest of the whole tribe;
their unwieldy bulk, likely to be disadvantageous where
214 GIANT TORTOISES. [CH. IV’
the struggle for existence was keener, is in all probability
to be referred to the same causes as the defenceless state
of the Dodo and other island birds.
The island of Mauritius was also inhabited quite
recently by gigantic tortoises which are now without
exception extinct. Dr Gadow in a recent communication
upon the subject’ distinguishes no less than six “ forms”
of these. He uses the word “form” because it seems
improbable that they have the full value of species; and
yet names are given to them without any such prefix as
“forma” or “var.” It is at least not usual for species of
the same genus—and all these giants belong to Testudo,
just like those of the Galapagos—to herd together in a
limited tract. Now five out of these six forms have
deposited their bones in one marsh; so much confused
were they, owing no doubt partly to the fault of those
who fished, them out, that in some cases the bones seem
to have entirely lost their mutual relations. Waiving
the question of species it is clear that great variability
reigned among these large and unpersecuted inhabitants
of the Mauritius—their freedom from enemies being also
perhaps indicated by the thinness of the shells. It is
incorrect to make the general statement that great size is
characteristic of island tortoises only, because the giant
Colossochelys of India and some other forms flourished
under continental conditions. But among living or but
recently extinct tortoises large size seems to have been
only attainable on these favoured because restricted spots,
1 Trans. Zool, Soc. Vol, x11.
CH. Iv] BATS OF NEW ZEALAND. 215
where natural selection imposed no check upon unwieldy
bulk.
Dr Dobson has pointed out the curious circumstance
that bats are not nearly so numerous in oceanic islands as
birds. From many considerations they ought to be;
their nocturnal habits and the general nature of their
insect food are characters which would favour successful
colonisation. The reason apparently for their comparative
scarcity in islands which must have been stocked with
them from the nearest mainland is correlated with the
comparative rarity of flymg objects. On another page
I direct attention to the fact that the insects of oceanic
islands are largely like the birds flightless. Now bats are
as a rule thoroughly aerial in their habits; they seek their
prey upon the wing. This fact, thinks Dr Dobson, is
largely responsible for the poverty of New Zealand in
Chiroptera.
Even in the British islands poor though their fauna
is there are eight times as many bats as in New Zealand.
One of the peculiar New Zealand bats, Mystacina tuber-
culata, “has the claws of the pollex and toes remarkably
elongated, very acutely pointed, and provided at the. base
of each. with a small talon projecting from its concave
surface near the base; the wings are peculiarly folded so
as to occupy the least possible space; and they and the
interfemoral membranes are preserved from injury by
being encased, when so folded, in a specially thickened
part of the wing and interfemoral membrane, analogous to
the thickened part of the anterior wings in Hemiptera,
1 Ann, Mag. Nat. Hist. Sept. 1884.
216 ISLAND INSECTS. (cH. IV
and to the elytra of the Coleoptera; furthermore the
plantar surface of the foot including the toes is covered
with very soft and very lax integumental tissue deeply
wrinkled.” These peculiarities of structure, thinks Dr
Dobson, must have some relation to the habits of the bat.
The probability seems to be that the structure of the feet
gives to the animal an unusual power of grasping tightly
any rough surface like the bark of a tree, while the wings
not being needed when the creature is in such a situation
are protected from injury by being carefully stowed away
in the fashion described. Dr Dobson is of opinion that.
this bat instead of hunting its prey on the wing seeks it
upon the trunks and branches of trees up and along
which the bat crawls. This curious modification of struc-
ture therefore is probably an indirect effect of living upon
an island where there are but few flying insects. From
the same group of animals may be drawn another example
of modification of structure having a relation to habitat.
In the Bermudas, which are 700 miles from the American
coast, are two species of bats; but one only in the Azores,
which are closer to the island of Madeira by about 150
miles. The presence of these animals is said to be due
to the occasional prevalence of violent storms. It is
remarkable that these species have a robuster and more
hairy body, which would of course tend to endow them with
a greater power of withstanding the violence and coldness
of a long-continued gale.
Another highly remarkable association of structure
with locality is afforded by the flightless insects of many
oceanic islands. Attention has been already directed to
CH. IV] LEPIDOPTERA OF ISLE OF MAN. 217
the fact that in the Galapagos and Kerguelen many of
the insects are flightless. The same is the case with
other oceanic islands. But in other cases the insects
have larger wings than their allies upon the mainland.
These two facts are both explained in the same way by
Mr Darwin. The small size of the islands and the frequent
prevalence of gales of wind would tend to blow the insects
out to sea, where they would in all probability perish.
Those individuals therefore which either had wings un-
commonly strong or were incapable of flight altogether
would have the best chance of maintaining their footing.
The same need has thus produced two effects of the most
opposite kind.
Prof. Eimer has remarked upon the fact that “the
butterflies of Sardinia are in general smaller and also
more darkly coloured than those of the mainland.” The
same thing exactly is met with in the case of the variety
of the small Tortoiseshell butterfly upon the Isle of Man.
This island has other insects which are darker in colour
than those upon the neighbouring mainland. Dianthecia
capsophila is a variety of the more usual D. carpophaga ;
in Ireland the examples of this variety are dark coloured,
but those of the Isle of Man are more darkly coloured
still. Mr Wallace mentions four other moths which show
some such difference from their representatives upon the
mainland. The somewhat rare Cirrhedia xerampelina is
not much darker than the mainland form but it differs
from it in the production of a characteristic yellow line.
The late Mr J. Jenner Weir, a well-known entomologist,
noted that several of the Geometer moths of the Hebrides
218 BIRDS OF GALAPAGOS. (cH. IV
had a tendency towards a greyer coloration than the
specimens of the same species on the mainland. This alte-
ration he was disposed to put down to a colour variation
of a protective significance in relation to the abundant grey
gneiss of the islands; it may however be a phenomenon
like the other instances that have been just mentioned.
It has been suggested that this prevailing melanism of
the insects of islands is an effect of the moist climates of
islands. On the other hand Mr Wallace noticed a
prevalence of white in the colour patterns of some of
the butterflies of the Moluccas and New Guinea, a
peculiarity more likely perhaps to be due to a possible
action of natural selection than the more usual darker
colour. The colour in this case would increase the con-
spicuousness of the insects; but in an island they would
run less risks from insect-eating foes and might therefore
develop more freely in certain directions than on the
mainland, where enemies are more numerous and com-
petition severer.
Precisely the same class of characters distinguish the
birds of the Galapagos islands. The genus Geospize, a
finch peculiar to the islands and consisting of eight species,
is of a dull colour to black, the darker hues being the
distinctive mark of age. “In old males,” says Mr Salvin,
“the plumage is almost uniformly black.” Such specific
names as “ fuliginosa” and “nebulosa” keep the pecu-
liarities of these insular birds in the mind. Cactornis,
another genus restricted to the islands, is “olivaceo-
1 On the Avifauna of the Galapagos Archipelago. Trans. Zool. Soc.
Vol. 1x. 1876, p. 447.
CH. Iv] OWLS OF GALAPAGOS. 219
fusca” dorsally, and the species is called by Messrs Sclater
and Salvin “pallida,”. which is significant. Mr Salvin
thinks that the species may have been founded upon
birds not adult. These statements however do not only
apply to genera which are peculiar to the islands and
occur nowhere else; indeed they would have much less
interest and significance if they did. One of the two Owls
living in the Galapagos, Asio galapagensis, is defined
by Mr Salvin as “ Asioni brachyoto similis, sed minor,
coloribus obscurioribus” &c. The Night Heron of the
Galapagos, whether it is a distinct species or merely a
variety of the common Nyctivorax violaceus, is stated to
be darker coloured than that species, and further instances
of a like nature might be brought forward from Mr Salvin’s
monograph upon the birds of these islands. Generally
speaking his Latin diagnoses of the species abound with
such words as “niger,” “nigerrimus,” “fuscus,” “fuli-
ginosus,” &c., and completely bear out what has been
already said of the colofation of island forms belonging
to this as well as of other groups of the animal kingdom.
CHAPTER V.
SOME THEORETICAL CONSIDERATIONS.
The bearing of the facts of distribution upon the
places of origin of different groups.
THERE seems to be little doubt that life first originated
in the sea, whence it spread to the fresh waters and so to
the land. We are not however concerned in the present
volume, which only professes to deal with the distribution
of terrestrial and a few fresh-Water groups, with this
problem.
But it is necessary to see how far the existing and
past facts of distribution enable the place of origin of a
particular terrestrial group to be indicated with prob-
ability. No exhaustive survey of the different groups of
the animal kingdom will be attempted; but a few facts
and suggested explanations will be put forward as
examples.
In some cases, of course, paleontology throws a clear
light upon the problem. The horse, for instance, came
into being in the new world, whence it migrated into the
CH. Vv] ORIGIN OF PARROTS. 221
old world, becoming for a time extinct in its place of
origin; it was subsequently reintroduced, apparently by
man. An instance of this kind shows how careful we
must be to guard against the assumption that that locality
where a given group is most abundant is its place of
origin. It is perhaps a stronger argument to use the
locality.of the more ancient forms of the group as being
probably the cradle of the race.
Fiirbringer has lately urged the antiquity of the genus
Stringops, the flightless parrot of New Zealand; this
coupled with the presence of abundant parrots in the
Australian region—many of them being primitive forms
that have preserved the ambiens muscle missing in many,
the normal arrangement of the carotids and a completely
developed clavicle—argues for that region as being the
starting-point of the Parrot tribe. Here we are not
helped to any great extent by paleontology.
The different regions into which the world is divided
possess, as has been pointed out in some detail, in every
case a characteristic fauna. That fauna may be or may
not be autochthonous; the American Edentates seem to
have arisen where we now find them, since no fossil
Edentates are known of the American type save in
America. Other countries are peopled by immigrants.
There can be no doubt that wherever the groups of ani-
mals that inhabit oceanic islands arose it was not in those
islands; there is clear evidence that they are the more or
less modified descendants of animals that found their way
across the sea in some way.
222 5; THE DINGO. [CH. V
The place of origin of the Marsupials.
The Australian region offers difficulties which have
perhaps been passed over too lightly. As is well known
the continent of Australia and some of the adjacent
islands to the northward are mainly characterised by
Marsupials. With the exception of the American
Opossums all the Marsupials are crowded into this com-
paratively limited tract of continent and island. In
addition to Marsupials there are of course the ubiquitous
bats, the Dingo dog and a few rodents, notably the genus
Hydromys, with more than one species. The Dingo has
been regarded as the feral descendant of a domesticated
dog introduced by man. M‘Coy has however demon-
strated the existence of fossil remains of this Carnivore in
the Pliocene deposits of Australia, the remains of a period
when there were no human inhabitants of the continent.
On the other hand the proof has been strengthened by
investigations which approach the matter from another
side. Nehring denies that the osteological characters of
this dog are those of a feral animal, and affirms that it
presents all the features of a truly wild race. The
indigenous nature of the rodent inhabitants of Australia
have not been called in question. The line which
separates the Australian from the contiguous Oriental
region passes between the islands of Bali and Lombok and
between Borneo and Celebes, the last-mentioned island
being in each case within the Australian division. Lyell
shows in a sketch map of that part of the world that this
line (which has been called “Wallace’s line”) nearly
CH. Vv] LIMITS OF AUSTRALIAN REGION. 223
coincides with a line marking off the range of the Indo-
Malayan and Pacific races of mankind. This remarkable
series of facts is usually accounted for in the following
way. The greater depth of water between the islands
mentioned probably indicates a longer time or separation
from each other than in those cases where the dividing
seas are shallower. Hence it may be assumed that the
dominant race of Mammalia in the earlier periods of the
earth’s history occupied Australia in common with the
rest of the world; at this time the deep separation
between the two regions, as we now admit them, took
place. Australia and the Australian region generally
would be well stored with Marsupials. ‘So too would the
Oriental region. But in course of time the wave . of
migration of higher types of mammals, the placental
mammals, evolved gradually from the Marsupial, would
extend eastward and improve the remaining Marsupials
off the face of the world; the deep straits already referred
to might be reasonably held to offer an impediment to
their further progress eastward in sufficient numbers at
any rate to compete successfully with the mammalian
possessors of the soil. Asa matter of fact the fringes of
the Australian region, the islands of Lombok and Celebes,
to wit, have received some few of these later migrants;
“a baboon, a wild cat and a squirrel” occur in Celebes;
while Macacus cynomolgus and one or two other placental
mammals reside in Lombok. This appears to be a
feasible explanation of the facts. But as already hinted
there are difficulties in the way of its immediate accept-
ance. To begin with, remains of the elephant have been
224 THE MONOTREMATA, {CH. V
dug up in Australia and in its furthest corner, viz.
Queensland. Furthermore, as the colonists know to their
cost, the common rabbit when artificially introduced has
proved capable of suiting itself with a marvellous degree
of success to the conditions found in Australia. In this
latter case no competition has had the least effect; and
even when hampered by repressive legislation aided by
the experiments of bacteriologists the rabbit has done a
good deal more than hold its own. It is clear therefore
that there is nothing in the “air” of Australia which is
in any way fatal to the constitutions of mammals in
general. Then why, if the Marsupials have disappeared
elsewhere, have they not also disappeared from Australia ?
The key to the explanation of this difficulty seems to be
the assumption that Australia is the native country of
that group. It will be remembered that in Australia
alone and in some adjacent territories (New Guinea) are.
there any representatives of the oldest order of Mammalia,
the Monotremata. The two existing genera Echidna and
Ornithorhynchus are unknown save in this part of the world.
It is generally accepted that the Monotremata stand
at the base of the mammalian series and that the
Marsupials stand between them and the higher mammals ;
the name Metatheria applied by Mr Huxley to the group
is an expression of this opinion. The very fact that
Marsupials abound in Australia is so far a proof that they
originated there; for they would have died out were they
not so suited. Over-population or the migratory instinct
caused many forms to leave the Australian region and to
spread over Europe and America, in which latter country
CH. Vv] IMPORTED ANIMALS IN AUSTRALIA. 225
alone they have persisted. In fact the Marsupials have
had the start in a country eminently suited to them and
have only been beaten in the struggle for existence in
regions subsequently settled in by them and therefore
perhaps less fit for their peculiar organisation. There
still remains the puzzle why some races of animals have
been able to establish themselves in Australia in spite of
the existing mammalian fauna, and why others have not.
The case of the rabbit shows that we cannot get out of
this difficulty by assuming that as much colonisation as
there was room for has as a matter of fact taken place.
On this view we should regard the presence of the
elephant as an unsuccessful attempt at colonisation. The
presence of comparatively speaking numerous placental
Mammals on the outskirts of the Australian region
renders it impossible to have resort to the hypothesis that
colonisation was at such rare intervals that only the
Dingo and the other few Australian placental Mammals
have had time to establish themselves. The only way
out of this difficulty which at present suggests itself is to
dwell upon the superior energy of the younger races of
the Palearctic region.
It is generally held that the desert of Sahara was an
open sea during the Miocene period ; and that this checked
‘the immigration or emigration of many purely terrestrial
forms, and that it therefore formed a boundary between
the Ethiopian and Palearctic regions. This boundary is
not accepted by everyone certainly ; but-it is bysome. Mr
Blanford has pointed out! that the geological views which
1 Presidential address to Geological Society 1890.
BZ, 15
226 PAST DISTRIBUTION OF MARSUPIALS. (CH. Vv
argued a sea occupying the region of the Sahara during
tertiary times are now believed to have been erroneous.
Zittel, says Mr Blanford, has shown that there is no reason
to think that any part of the Sahara has been sea since
the Cretaceous period. This fits in admirably with the
present and past distribution of the Marsupials and in quite
a convincing way. There is of course abundant evidence
that these mammals were common in Europe during the
mesozoic epoch, whether they originated there or not.
Now if there was then land connection with the African
continent why did they not migrate there as well as to
Australia and to America? It is of course possible that
they did and that they have since become extinct.
_ Madagascar however has to be considered; many writers
‘have pointed out that Madagascar appears to have
preserved some of the more ancient mammalian inhabi-
tants of the Ethiopian continent. In any case it seems
certain that many of the newer immigrants into Africa
never succeeded in getting as far as Madagascar. There
are so many analogies of a kind between Madagascar and
Australia that the negative fact that Marsupials do not
occur there gets a certain importance. If however the
severance between Africa and Europe was of earlier date
than is commonly held we have a possible explanation of
the entire (?) absence of Marsupials from the former
continent. -Besides, their absence sheds perhaps an
oblique light upon my suggestion that the group origin-
ated in Australia. The numbers in Europe may have
been small, and there was therefore no pressure such as to
lead to migration.
CH. V] SOUTHWARD MIGRATION OF ANIMALS. 227
Theory of the Polar origin of Life.
The theory of the polar origin of life’ is, as regards
terrestrial and fresh water vertebrates rather seductive.
On this theory it is clear that the further away from the
north pole the more archaic will be the types of animals ,
met with; and on the contrary the newer groups will
have moved away to.a less distance. Among the Mammalia
this is strikingly exemplified of course by the Marsupials,
once existing in great variety mm Europe and North
America. They are now absolutely extinct in Europe and
but feebly represented in North America. The survivors
have been pushed in to the furthest corner of the world—
the Australian continent, and some of the islands to the
north. The bulk of the American Opossums are confined
to the Neotropical, i.e. the more southern regions of the
American continent, only a single species occurring in
North America. This it is presumed upon the theory
under discussion is due to the fresh development of types
of life in the polar regions which have forced the older
and less vigorous forms of life to emigrate; a continued
efflux of waves of life spreading out from the place of
origin push further away the races which have the start.
Everyone is agreed that the Struthious birds are in all
probability an ancient race, or perhaps races, for the unity
of the group is now-a-days rather called in question.
Here again we meet with no northern types at all; North
Africa is the northern limit of the birds, and the vast
1 See Haacke, Biol. Centralblatt v1.
15—2
228 ANCIENT TYPES OF SOUTHERN HEMISPHERE. [CH. V
majority are in the most southern parts of the globe;
New Zealand itself had quite recently a number of species
as great as all the existing forms. The northern types of
birds, for instance the sandpipers, crows and hosts of
others, embrace no forms that can be regarded with any
probability as more ancient than the Ostrich tribe.
Among Reptiles the Hatteria, allied to the triassic
Hyperodapedon, has been driven quite to the verge of
inhabitable country; it has even got beyond New Zealand
to a few small islands off the coast. Turning to another
group of animals, the Dipnoid fish exemplify what has
been said in a forcible way; the three existing genera
Ceratodus, Protopterus and Lepidosiren are confined
respectively to Australia, South America, and certain
parts of Tropical Africa. The fossil remains of Dipnoi
are common in the more ancient strata of this country
and of North America. Even invertebrates fall in with
the theory to some extent. It seems on all grounds
reasonable to conclude that the genus Lumbricus, and
its immediate allies, are the most modern existing forms ;
these genera are precisely those which are indigenous to
the northern hemisphere only, where they form, with
a few exceptions, the only earthworms met with.
The more archaic Perichetide, Acanthodrilide and
Cryptodrilide are characteristic of the southern hemi-
sphere while the Acanthodrilidze which are very possibly
the oldest existing family of the group are particularly
antarctic in their range. The fresh water Crayfishes fall
in with the other groups cited; and the facts in their
distribution and structure agree entirely with those of
CH. Vv] RANGE OF ASTACIDA. 229
the earthworms. Huxley! has divided the family into
two families the Potamobiide and the Parastacide; the
former are confined to the northern the latter to the
southern hemisphere. Of the Potamobiide there are but
two genera Astacus and Cambarus. In both of these the
pleurobranchs are greatly reduced, indeed in Cambarus
they are completely absent. Asin Astacus there are distinct
rudiments of the pleurobranchs belonging to several pairs
of appendages, in addition to one pair completely developed;
the inference appears to be that the extra pleurobranchs
have in the course of time been lost. Now in all the
Parastacidee with the exception of Astacoides there are
four pairs of fully developed pleurobranchs, thus indicating
an earlier type. Furthermore the genera of the southern
hemisphere, “in which the apices of the podobranchiz are
not separated into a branchial plume and a well developed
lamina, present a less differentiated type of branchial
structure than that which obtains in Astacus and Cam-
barus.” Prof. Huxley himself is inclined to postulate the
existence of a marine ancestor of world wide distribution
which entered the rivers of the northern and the southern
hemisphere and diverged in different ways in each hemi-
sphere; but this leaves unexplained why the antarctic
genera should have retained more primitive characters
than the Crayfishes of the north.
There is another essential if the polar theory of the
origin of life is to be accepted. To establish this theory
upon a firm basis it will have to be proved that the
faunas of the different countries become more and more
1 The Crayfish in International Sci. Series.
230 ARCTIC ANIMALS. (CH. V
divergent the further they are removed from the hypo-
thetical seat of origin. This can be defended by a series
of facts. There has been of late a considerable amount of
discussion as to the value of the Palearctic and Nearctic
regions of Mr Sclater. It has been proposed to unite
them into one common region to which the name Holarctic
has been applied by Prof. Newton. This is accepted by
Dr Heilprin in his work upon Geographical Distribution.
More recently Mr Wallace has defended the retention of
the two separate regions. The present object is not to
attempt to decide upon the relative values of these two
opinions but to emphasise the fact that there has been a
discussion, and to point out that there never has been any
question as to the distinctness of two such regions as the
Neotropical and the Oriental. An ingenious reconciliation
has been suggested by Dr Hart Merriam who would
institute a Boreal region cut off from Nearctic, and joined
to the Palearctic leaving the rest of the Nearctic alone
as a distinct “Southern” region. This proposal brings’
into prominence the very close resemblance of the circum-
polar fauna; indeed out of the 30 genera of mammals
in the Boreal region only 10 are peculiar to America.
If we were to adopt a slightly different plan and cut off a
boreal region or Arctic region as it has been termed from
both Palearctic and Nearctic the almost complete identity
of the circumpolar fauna would be clearly demonstrated.
Such animals as the Reindeer, the Glutton, the Elk, the
Lemming, the Arctic Fox are circumpolar in range.
Between the Palarctic and the Nearctic, after this large
slice has been cut off from both, there is not a little
CH. Vv] FOSSIL FLORA OF GREENLAND. 231
likeness, though there are also differences. Moving
further south the differences increase until the resem-
blances almost entirely vanish.
It is unnecessary to recapitulate the characters of
the faunas of the several regions here, as the matter has
been already treated of. Broadly speaking it is unques-
tionably the fact that the differentiation of the different
regions gradually increases as we pass southwards from
the north pole. We cannot of course hope to reduce to
an exact table the progressive differentiation of the fauna
along the lines of migration; some have moved more
rapidly, others have lagged behind; while structural
changes have proceeded more rapidly in some groups
of animals than in others. But a survey of the facts
tends to prove the general accuracy of the conclusion that
the differentiation of faunas proceeds more rapidly the
further we get from the pole.
It is obvious that if life originated at the north pole
the conditions of climate must have been more favourable
than at present. That this was so there is abundant
evidence to prove. The existence of a luxurious and at
least subtropical fauna in the arctic regions during the
Miocene period is justly termed by Mr Wallace “one of
the most startling and important of the scientific discoveries
of the last 20 years.” In remote Greenland we find
abundant and well preserved remains of chestnut, walnut,
plum, vines and even magnolias. Further north still in
lat. 78° and 79° there was in Spitzbergen an almost equally
rich fauna, of which one member the swamp cypress
(Taxodium distichum) is now a dweller in the southern
232 GLACIAL EPOCHS. [cH. Vv
United States. Water lilies, pond weeds, and an iris,
flourished at the same time in the same place. This
however does not indicate by any means the limits of
life towards the pole; in Grinnel land distant only
8} degrees from the pole itself there was a flora composed
of poplars, elms, hazels and the swamp cypress again.
This warm period preceded the glacial period, which of
course put an end to the flora and fauna or else drove it
southwards. It is the opinion of many that the glacial
period was not an isolated phenomenon but the last in
a series of many glacial periods. If this were so
and if they recurred with tolerable frequency as is
again the opimion of many, all question of a polar
origin of life would be out of the range of possibility.
This view of the matter has been mainly based upon
two series of facts. In the first place it is argued that
these glacial periods have been due to the variations
in the obliquity of the earth’s orbit, which alternates
from a more to a less pronounced ellipse. This would
bring about in conjunction with the rotation of the
earth on its own axis long cold winters and short hot
summers as well as the reversed condition. The former
would it is thought account for glacial periods. That
these have taken place in the recurrent fashion demanded
by this astronomical cause is attempted to be proved by
the existence of erratic boulders imbedded in the sedi-
mentary rocks belonging to past epochs. Mr Wallace
however holds that this cause is not of itself sufficient to
cause excessive glaciation; it is necessary also to have
continuous land surfaces and high mountains to retain the
CH. Vv] PALZOZOIC GLACIAL PERIODS. 233
snow and ice and to prevent the influx of warm currents
from more southern latitudes. The undoubted boulders
he regards not as evidence of exceptional glaciation, but
as evidence of high mountains with glaciers which carry
down these boulders ; this is not inconsistent with a warm,
even tropical, temperature at their base. It is not until
we reach the Permian period that Mr Wallace thinks that
a severe glaciation occurred. In the west of England
there are beds of ice-borne rocks which must have been
carried for a distance of fifty miles and this together with
the poverty of the fauna and flora are indications of a
glacial period. If however we consider as Prof. Huxley
did in 1870 that even the highest group of animals the
mammalia probably originated well within the Paleozoic
period, since it has taken from the commencement of the
Eocene to almost to-day for so small a modification as the
reduction of the horse’s foot from the five-toed to the
one-toed condition, even this remotely distant glacial
epoch will be sufficiently near to exclude all possibility
of the polar origin of mammalian, let alone all other
vertebrate and invertebrate life. We may take it therefore
that the polar regions enjoyed a mild or even a warm
climate throughout the tertiary and secondary epochs,
but it has been pointed out that in Carboniferous and
Silurian times the temperature judging from the fauna
and flora was of the same kind; this however is of no
importance from the present point of view if the Permian
glacial period really took place as the evidence seems to
assert.
INDEX.
Acanthisita, 201
Acanthodrilide, 58, 60, 65
Acanthodrilus, 57, 60, 65, 66, 67,
111, 169, 170; georgianus, 67;
Kerguelenensis, 194; monocystis,
65; verticillatus, 180
Aceros, 106
AXolosoma, Range of, 140
luroidea, 188
Eluropus, 90, 92
Alurus, 90, 92, 106
Africa, Scorpions of, 57; and
Europe, Affinity between, 43
Agaristide, 130
Aglossa, 47
Alectoromorpha, 75
Alectoropodes, 27, 28, 29
Alligator, 43, 44; sinensis, 44
Alligators, Mississippi, 3
Allolobophora, 152; Japonica, 153
note
Allurus, 152; tetradrus, 57
Amblyrhynchus, 148, 196, 197
America, Scorpions of, 52
Amphibia, Dispersal of, 145; Uro-
dele, 47; and fishes, 178
Amphignathodontide, 48
Amphisbena ridleyi, 191
Amphisbenide, 41
Anabas scandens, 2
Anacharis, 128
Anelytropide, 41
Anguide, 41, 42
Animals, Habitats of, 3; General
facts of the distribution of,
1-70; Introduced, 129; Land,
distribution of, 4; Locality and
station of, 5; Means of disper-
sion of, 134; Range of, 7; Ter-
restrial and aquatic, 2
Annadrilus, 63
Annelids, 1388; Terrestrial, 168
Anoa, 107
Anodonta, 144; anatina, 142
Anomalopteryx, 202
Antarctic Continent, 164
Antarctogera, 74
Anteaters, Range of, 31
Anteus, 64
Anthropopithecus calvus, 99, 101
236
Antilocapra, 96
Apes, Anthropoid, 106
Apis mellifica, 128
Apoxypodes, 50
Aptenodytide, 76
Apteryx, 200, 202, 210
Aptornis, 202
Aramus, 109
Archisometrus, 51
Arctocebus, 102
Arctogera, 74, 75
Arctonyx, 106
Arcturides cornutus, 125
Arcturus americanus, 125; baffini,
125; coppingeri, 125; furcatus,
125; oculatus, 125; Shallow
water and deep sea, 126; steb-
bingi, 125; studeri, 125; Range
of, 125
Argilophilus, 69
Argus, 29
Arion, 145
Armadillos, 31, 111
Arthropods, 17
Asio galapagensis, 219
Aspidonectes, 148
Astacilla, 125, 126; marionensis,
125
Astacus, 229
Athecrm, 38
Atheriogwa, 75
Atherura, 104
Attagis, 110
Australia, Frogs of, 172
Australian Region, Families pe-
culiar to the, 113, 114; sub-
regions, 116, 117
Avifauna of Australian region, 115
Baboon, Gelada, 101
INDEX.
Badger, its habitat, 5
Balewniceps, 100, 101
Barbets, 110
Bassaris, 25, 94, 109, 112
Batrachia, Distribution of, 47
Batrachians, 80
Bats of New Zealand, 215
Bear, Present and past range of
the, 154
Bears, Distribution of, 22
Beetles, ‘‘Hercules and Goliath,”
129
Belemnites, 182
Belodon, 148
Benhamia, 59, 65, 67, 170
Bernicla sandvicensis, 204
Bernissartia, 44
Bipalium, 55; Kewense, 54, 55
Boas, 46
Boidee, 46
Bolieria, 46
Brachylophus, 77
Brachytarsomys, 188
Brachyurus, 111
Bradypodidm, 31
Bradypus, 31, 111
Brazilian sub-region, 111
British Isles, Fauna of, 183
Brontornis, 167
Bucerotide, 75
Buto dialophus, 77, 147 note
Bufonide, 47
Buteo solitarius, 204
Buthide, 50
Butterfly, Large copper, 7
Cacatuide, 114
Cactornis, 197, 218
Caiman, 48, 44
Californian sub-region, 36
INDEX.
Callidrilus, 63
Calodromas, 111
Calophrynus, 178
Camarhynchus, 197
Cambarus, 229
Canadian sub-region, 97
Cancroma, 110
Cannonopsis, 194
Capra sgagrus, 21; caucasica, 21;
faleoneri, 21; hylocrius, 22;
ibex, 21; jemlanica, 21; pal-
lasii, 21; pyrenaica, 20; severt-
zowi, 22; sibirica, 21; sinai-
tica, 21; walie, 21
Capromys, 112
Cariama, 109, 167
Cariamide,. 76
Carinate birds, 82
Carpococcyz, 107
Casarca, 46
Cassowaries, Distribution of, 23
Cassowary, Species of, 23
Castniidxw, 130
Casuarius australis, 23; Beccarii,
24; Bennetti, 24; bicaruncula-
tus, 24; Edwardsi, 23; galeatus,
23; laglaizei, 24; occipitalis, 24;
picticollis, 23; Salvadorii, 23;
uniappendiculatus, 23; Wester-
manni, 23
Cathartide, 76
Celebes, Fauna of, 106
Central or Rocky Mountain sub-
region, 96
Centropus, 36
Centrurus, 52
Ceratodus, 228
Ceratophrys ornatus, 48
Cercophonius, 52
Cereopsis, 202
237
Ceriornis, 89, 93, 106
Certhidea, 197
Ceylonese sub-region, 105
Chalarodon, 189
Chalk and Ooze, 158
Chamea, 96
Chameleon, 32, 190
Chameleons, Range of, 41
Chasmorhynchus, 129
Chauna, 109
Chelonia, Distribution of, 38
Chelydide, 39
Chelydride, 38
Chilian sub-region, 110
Chimpanzee, 13, 68, 99
Chionis, 166
Chiromyide, 11
Chiromys, of Madagascar, 14
Chlamydophorus, 32, 110
Chosropotamus, 100
Cholepus, 31
Chrysochloridx, 102
Cidarids, 158
Cinisternide, 38
Cirrhedia xerampelina, 217
Civet, The, 91
Cladocera, Eggs of, 136
Cnemiornis, 202, 210, 211; calci-
trans, 202
Ccelodon, 34
Coloplana, 55
Coliids, 100
Colossochelys, 214
Colour and distribution, 118
Colubride, 46
Condylura, 97
Conolophus, 196
Coracopsis, 189
Corallus, 46
Coregonus vandesius, 8
238
Cornufer, 47, 77
Cosmopolitan genera, 9; groups,
8; species, 10
Cotyloplana, 55
Coua, 189
Cracide, 27, 28, 30, 31
Cricetomys, 90
Criodrilus, 64
Crocidura, 188
Crocodile hidden beneath a hay-
stack, 154
Crocodiles, Distribution of, 43;
Marine, 148
Crocodilus, 43, 44; palustris, 45
Crossoptilon, 93
Crotophaga, 36, 94
Crustacea, Antarctic, 161
Crustaceans, Isopod, 161
Cryptodira, 38
Cryptodrilide, 58; Range of, 68
Cryptodrilus, 60, 69
Cryptoprocta, 14, 188
Ctenodactylus, 91
Cuckoos, 105; Distribution of, 35;
Fossil, 37; Old World and New
World, 36
Cuculide, Distribution of, 35
Cuculus canorus, 36
Cuseus, 77
Cyathopoma, 179
Cyclostoma, 144
Cyclostomatids, 179
Cyclotopsis, 179
Cycloturus, 31
Cynomys, 97
Cynopithecus, 104, 107, 116
Cystignathide, 48, 172
Dactylethride, 47, 49
Dama, 91
INDEX.
Dasornis, 167
Dasypodide, 31, 33
Dasypus, 32
Deinodrilus, 60, 65, 66, 169
Dendrobatide, 48
Dendrogea, 47, 74
Dendrolagus, 117
Deodrilus, 69
Dermatemydide, 38
Diacheta, 64
Diantheecia capsophila, 217
Diatryma, 167
Dichogaster, 69
Didelphys, 109
Didunculide, 77
Digaster, 69
Dingo, The, 115, 222
Dinornis, 200, 202
Dinornithide, 167
Dionychopodes, 50
Diplocardia, 65, 67
Diplocentride, 53
Diplocentrus, 52, 53
Diporocheta, 61, 169
Discoglosside, 48
Discophidz, 49, 178
Distechurus, 117
Distribution, 118, 119, 124; Dia-
grams of, 119-121; Discontinu-
ous, 15; Geographical, 4; Plans
of, 81, 82; Mr Romanes on, 132;
and evolution, 131
Dolichoplana, 56
Dorcopsis, 117
Doriopsis, 84
Doris, 84
Drepanidide, 77, 204
Dytiscus, 143
Earth-worms, Aquatic, 138; Dis-
INDEX.
tribution of, 57; Ethiopian, 67;
Families of, 58, 59; of Mada-
‘gascar, 180; of Mauritius and
Rodriquez, 181; of New Zea-
land, 66; of West Indies, 64
East African sub-region, 101
Eastern or Alleghany sub-region, 97
Echidna, 32, 224
Echinoderms, Fossil, 182
Echinoids, 158
Eetemnorhinus viridis, 194
Edentates, 76, 111; Distribution
of, 31; Extinct, 34; Old World,
32; Structure of, 33
Elainea ridleyana, 191
Elaphodus, 92
Elaphrornis, 106
Elasmognathus, 109, 112
Elephant, Indian, 104
Elseya, 39
Embryonopsis halticella, 194
Emeus, 202
Enhydra, 96
Enchytreide, 139
Ethiopian region, Families pe-
culiar to, 98; genera peculiar
to, 98, 99; sub-regions, 101
Btroplus, 178
Eublepharide, 41
Eudrilidz, 58
Eudriloides, 68
Eudrilus, 58, 67
Eupleres, 188
Eupetes, 107
European sub-region, 91
Eurypyga, 109, 111
Eutheria, 86
Evolution and Distribution, 131
Fauna, affinities of, 192
239
Faunas, Influence of geological
terrain upon, 136; Similarity
of the, in different . countries,
129; Synchronous, 163; of
Tropical countries, 130
Fernando Noronha, Fauna of, 190
Fish, Fresh-water, 171
Flat worms, 3
Flightless birds, 213
Francolinus Kirki, 8; pictus, 29
Fregilupus, 11
Frog, The edible, 146
Frogs and Toads, 47
Galapagos, Birds of the, 218;
Fauna of the, 195; Insects of
the, 198; Owls of the, 219
Galaxias, 171; attenuatus, 171
Galaxiide, 171
Gallinaceous birds, Distribution of,
26; Structure of, 28
Gallus, Species of, 29
Gammarus, 192
Garrulus, 18; glandarius, 19
Gastornis, 167
Gavialis, 43, 44
Geckotide, 40
Geobia subterranea, 55
Geococcyx, 36, 96
Geodesmus, 55
Geographical distribution, 4
Geomalacus maculosus, 186
Geophilus ridleyi, 191
Geoplana, 55, 56
Geoscolex, 64
Geoscolicide, 58, 60, 62, 63, 181
Geospiza, 197, 218
Glauconiide, 46
Globigerinz, 158
Glyphidrilus, 63
240
Goats, Wild, Range of, 21
Gordiodrilus, 66, 69
Gorilla, The, 11, 101
Graptolites, Range of, 160
Grosphus, 51
Gruide, 75
Guinea-fowls, 29
Gymunura, 106
Hallomys, 188
Halobates, 2
Haploceros, 96
Haplochitonide, 171
Haploodon, 96
Harpagornis, 203
Hatteria, 12, 14, 40, 201, 210,
228
Helicina, 179
Heliodrilus, 68
Helix desertorum, 144
Heloderma, 42
Hemichromis, 178
Hemiphractide, 48
Henlea ventriculosa, 7
Hesperomys, 90, 196
Heteralocha, 201
Heterocephalus, 101
Heterodon, 189
Hippopotamus, 14, 100
Hoplurus, 189
Hormogaster, 63
Hormurus, 51
Humming-birds, 132
Hyena, 91
Hydromys, 222
Hydrophasianus, 105
Hydropotes, 92
Hylobates, 104
Hylodes, 48
Hyomoschus, 102
INDEX.
Hyperiodrilus, 68
Hypocolius, 101
Hypogeomys, 188
Ibex, 24; Scarlet, 110; Spanish,
20
Ibexes, Distribution of, 20
Iguanide, 41
Tlyogenia, 63
Tlysiide, 46
Indian sub-region, 105
Indo-Chinese sub-region, 106
Treland, Mollusca of, 186
Islands, Anomalous, 210; Com-
parison of, 205
Isle of Man, Lepidoptera of the,
217
Isometrus, 51
Jays, Distribution of, 18
Kerguelen, Fauna of, 193
Kerria, 65, 66, 169
Koala, 117
Kynotus, 63, 180, 181
Lacertidw, 42
Lacertilia, Distribution of, 40
Lagopus albus, 29; scoticus, 184
Lagothrix, 111 :
Lama, 110
Leimacopsis, 56
Lemurs, 41, 100, 176; Diagram
of range of, 123; Genera of,
187
Lepidosiren, 228
Lepidoptera, Range of, 6
Leptopoma, 179
Leptosoma, 189
Liopelma hochstetteri, 48, 201
INDEX.
Liothrix, 106
Lizard, African, in Cumberland,
154
Lizards, Distribution of, 40; Mo-
nitor, 190
Lophophorus, 89, 93
Loris, 105
Loxocenius, 46
Loxops, 204
Lumbricide,
European,
pean, 153
Lumbricus, 63, 152, 228; papil-
losus, 186
Lusciniola, 92
Lutronectes, 92
Lybiodrilus, 68
Lyceena agestis, 186; Artaxerxes,
186
Lycaon, 102
Lymnea involuta, 186; peregra,
141; trunculata, 142
Lynx, The, and the Bear in Europe,
155
58, 62, 63,
154;
169;
Extra-Euro-
Mabuia punctata, 191
Macacus, 104; cynomolgus, 223
Madagascar, Fauna of, 187
Malayan sub-region, 106
Mammalia, 85, 86, 87
Mammals, Distribution of, 74;
Past history of, 86; and Zoo-
logical regions, 85
Man as a distributing agent, 152
Manatee, 2
Manidex, 32
Manis, 33, 34, 104
Mantchurian sub-region, 91, 92
Mantella, 48
Manucodia, 117
B. Z.
241
Marsupial Mole, 117
Marsupialia, 76
Marsupials, 56, 114, 117, 222,
225, 226
Mascarene birds, 177
Mediterranean sub-region, 91
Megalapteryx, 202
Megapodes, 114
Megapodide, 27, 28, 30, 31
Megapodius, 107
Megascolex, 61; armatus, 180, 181
Megascolicide, 62
Megascolides, 60, 69
Megatheriidez, 33, 34
Megatherium, 34
Meleagride, 27
Meleagris, 30
Mesites, 101, 189
Metatheria, 86
Mexican sub-region, 111
Microcheta, 63
Microdrilus, 69
Microglossus, 117
Microplana, 55
Microscolex, 60, 68,.70, 111, 169,
170, 202
Migration, 150, 151
Millsonia, 69
Mimus trifasciatus, 198; parvulus,
198
Mollusca, Characters of, 84; Dis-
persal of, by insects, 143; Dis-
persal of land and fresh-water,
140; Migrations of, 142; of
ponds, 141; and Zoological
regions, 83
Moniligastride, 58
Monitors, 42
Monkeys, 11, 76
Monotremata, 12, 76, 86, 113, 224
16
242
Moschus, 90, 92
Mud Fish, The, of Africa and
America, 3
Mus musculus, 193; rattus, 210
Musophagide, 100
Mydaus, 106
Myogale, 91
Myrmecobius, 117
Myrmecophaga, 33, 34, 111
Myrmecophagide, 31
Myro, 194
Mystacina tuberculata, 200, 215
Myxomys, 112
Naia tripudians, 149
Nearctic Region, 93; sub-regions,
96
Nebo, 53
Nectogale, 92
Nematoda, 136
Neodrilus, 65
Neogera, 45
Neosorex, 96
Neotropical Region, families pe-
culiar to, 207; genera peculiar
to, 108; Sub-regions, 110
Nepa, 142
Nesomys, 188
New Guinea, the original home
of the Cassowaries, 24
New Zealand, Bats of, 215, 216;
extinct birds of, 202; Fauna of,
199; Flora of, 127
Notogma, 56, 75, 76
Notonecta, 143
- Notornis, 201, 211
Notykus, 68
Novo-Zealanian sub-region, 118
Numida, 30
Numidide, 27
INDEX.
Nyctereutes, 92
Nycticorax violaceus, 219
Nyctiornis, 105
Oceanic Islands and submerged
Continents, 157
Oceans, Permanence of, 156
Ocnerodrilus, 70
Octochztus, 60, 65, 66, 169
Ocydromus, 201
Cineis jutta, 16
Oligocheta, 58; Dispersal of, 138,
139; terricole, 169
Onchidium, 3
Onychocheta, 64
Opisthacanthus, 53
Opisthocentrus, 53
Opisthodactylus, 167
Opisthocomide, 27, 76
Opisthocomus, 11, 27, 109
Orang, 104, 106
Oriental Region, Families peculiar
to the, 103; genera peculiar to
the, 103; Sub-regions, 105
Ornithogera, 75
Ornithorhynchus, 224
Ornix devoniella, 11
Orycteropodide, 32, 34
Orycteropus, 33, 34
Ostolemus, 43, 44
Ostracod, 192
Ostrich tribe, 29
Otidie, 75
Ovibos, 97
Ovis montana, 96
Owl, The Barn, 7
Pachyornis, 202
Palearctic Region, 88, 89; Sub-
regions, 91
INDEX.
Paleogea, 45
Paleoperdix, 29
Palwophonus, 50
Palxornis, 105
Paleortyx, 29
Palamedea, 109
Palamedeidw, 76
Paludina, 144
Panthalops, 92
Panurus, 91
Papuan or Austro-Malayan region,
116
Paradisea, 117
Paretroplopus, 178
Parrots of the Australian region,
115; Origin of, 221
Parus ater, 184; britannicus, 184;
palustris, 16; rosea, 184
Passerines, 72-74
Patula hookeri, 194
Peacock, 29
Pectinator, 101
Pedetes, 102
Pedioccetes, 97
Pelamys, 149
Pelomedusa, 39
Penguins, 166
Pennula ecaudata, 204
Pericheta, 59, 61, 62, 169, 181;
indici, 180; madagascariensis,
180; mauritiana, 181; robusta,
181
Perichetide, 61, 62
Perionyx, 61; zanzibaricus, 62
Periophthalmus, 3
Peripatus, 16, 26; Range of, 17
Peristeropodes, 27, 75
Perodicticus, 101
Perosuchus, 43, 44
Pheenicophaés, 35, 37
243
Phasianide, 27
Phasianus, 89, 93
Pheasant, 29
Philodryas, 189
Phororhacus, 167
Photodilus, 105
Phyllodactylus, 196, 197
Phytogeography, 4
Phytosus atriceps, 194
Piaya, 36 ‘
Pigeons of the Australian region,
115
Pipa, 48
Pipide, 47, 48
Pisidium pusillum, 141
Pithecia, 111
Pitta, 102
Pixys, 39
Plagiocheta, 60, 65, 66, 169
Planarians, Land, 53, 56
Planorbis, 191, 192; corneus, 141;
nautilus, 141
Platacanthomys, 105, 106
Platypus, 117
Platysternide, 38
Pleurodira, 38
Plumatella, Statoblasts of, 136
Plutellus, 69
Podocnemis, 39, 40
Peecilophycis, 194
Polar origin of life, Theory of,
227
Polycladus, 56
Polynesian sub-region, 117
Polyommatus dispar, 185
Polytoreutus, 68
Pontodrilus, 57, 70
Pontoscolex, 58, 64, 70; corethru-
rus, 192
Poospiza, 97
24.4
Porcupine, 91
Potamocherus edwardsi, 188
Potamogale, 102
Prechidna bruijnii, 117
Priodon, 32
Procarpa, 92
Productus, 163
Prosthemadera, 201
Proteles, 102
Protopterus, 228
Psammomys, 91
Pseudapteryx, 202
Psittinus, 105
Psophia, 109, 111, 167
Psophiids, 11, 76
Pteroclide, 75
Pteromys, 104
Pteropide, 77
Pucrasia, 93
Puma, The, 94
Pupa, 85
Pygopodide, 42
Pyrophthalma, 92
Pythons, 46
Querquedula eatoni, 193
Rabbits in Australia, 129
Rana esculenta, 146; guppyi, 47,
77; mascarina, 176
Ratite, 76
Region, Holarctic, 78, 80; Poly-
nesian, 77
Regions, Arctic and Antarctic, 76;
Hepetological, 79; Mr Huxley’s,
75; Mr Sclater’s, 72, 78, 88;
Use of birds for defining, 82
Reptiles, Dispersal of, 147; of
the Galapagos, 196; and Ocean
barriers, 149
INDEX.
Restricted groups, 10
Bhacophorus, 49, 178; reinwardti,
49
Rhea, 111; Distribution of, 19;
Species of, 20
Rhea americana, 19, 20; darwini,
19, 20; macrorhyncha, 19, 20
Rhinoceros, 99
Rhinochetide, 11, 77
Rhinodrilus, 64
Rhynchocephalia, 12
Rhynchodemide, 55
Rhynchodemus, 55
Rodents of Madagascar, 188
Rotifers, 136
Salmo perisii, 185
Salpinctes, 97
Sandwich Islands, Fauna of, 203
Schistocerca literosa, 199; melano-
cerca, 198
Scincide, 40
Scopus, 100
Scorpions, Distribution of, 49
Scotophilus tuberculatus, 200
Sea-lions, 168
Sea-serpent, 168
Selasphorus rufus, 97
Seleucides, 117
Semnopithecus, 106
Serolis, 172; distribution of, 175;
species of, 173, 174
Serolis carinata, 174, 176; minuta,
175; paradoxa, 174; septem-
carinata, 175
Seychelles, Mollusca of, 179
Siamanga, 104
Siberian sub-region, 91, 92
Siphonogaster, 63, 138
Skunk, The, 94, 109
INDEX.
Sloths, Range of, 31
Snakes, Colubrine,
bution of, 46
Solenodon, 112
South-African sub-region, 102
Sparganophilus, 64, 187
Sparrow, The, in the U. S., 128
Spherium lacustre, 141
Sphargis coriacea, 38
Spirobolus noronhensis, 191
Steatornis, 110
Sterna virgata, 193
Sternotherus, 39
Stringops, 201, 221
Strix flammea, 7, 197
Stuhlmannia, 68
Stumpffia, 48
Sturnornis, 106
Subarctic sub-region, 97
Sub-regions, Mr Mitchell’s scheme,
122°
Succinea, 144; Eggs of, 142
Sus, 116
46; Distri-
Teniogale, 105
Talegalla lathami, 29
Tamandua, 31
Taoperdix, 29, 30
Tapinostola bondii, 6
Tapirs, The, of America and India,
131; Indian, 106; Malayan, 104,
109, 111
Tarsius, 104, 106, 116
Tatusia, 32
Taxodium distichum, 231
Teguexin, 42
Teiide, 42
Testacella, 145
Testudo, 39, 214
Tetrao urogallus, 28
245
Tetraonide, 27, 30
Thaumalea, 89, 93
Thecophora, 38
Thinocoris, 110
Thylacine, 14, 117
Timelia, 107
Timeliide, 104
Tinamous, 76
Tityobuthus, 51
Tityus, 53
Todus, 112
Tolypeutes, 32, 110
Tomistoma, 43, 44
Tortoises, Distribution of, 38;
Giant, 213, 214
Trichocheta, 64
Trinephrus, 69
Trionychoidea, 38, .39
Trionyx, 39
Trochilide, 76
Trogons, 110
Tropidonotus tessellatus, 149
Tropidurus, 196
Tubifex, 7
Turbellaria, Triclad, 54
Tykonus, 64 *
Typheus, 69
Typhlopide, 46
Ungulata, 76
Ungulates, The, 104
Unio, Australian, 141
Upupide, 75
Urobenus, 64
Urocissa, 106
Uropeltide, 46
Urotrichus, 96
Ursus, 22; arctos, 90, 154; ferox,
90
Urva, 106
246 INDEX.
Volucella, 129 Wombats, 117
Vanessa cardui, 7
Varanide, 42
Vespertilionide, 77
Vireo gracilirostris, 191
Vulturidz, 75
Xenicus, 201
Xenopeltide, 46
Xenosauride, 42
Xenurus, 32
Zenaida maculata, 191
West-African sub-region, 101 Zonites, 85
West-Indian sub-region, 112 Zoogeography, 4
Woodpecker, 32 Zosterops, 129
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